Delays with the general contractor, no deadline set according to § 650 Building Code

Hello,
we are having problems with our general contractor (GU). We actually thought we had chosen a solid GU, especially since we also know satisfied people who built with this GU and were very happy with them.
A brief overview of our construction project: Since the end of November, we have had the building permit and are currently working on the selection of materials and finishes (Bemusterung). The goal was to complete the selection by the end of February, after the initial appointment in January. However, since February there has been hardly any communication, our emails are ignored, questions about the status or possible problems go unanswered. Phone calls are also curtly dismissed.
Considering that we have been working on the selection since the end of November, which was when the building permit was granted and the prerequisite for the selection appointment, we find this quite concerning and the duration of the selection process actually unacceptable. Who has a selection process lasting six months...
Additionally, during the selection protocol, it was again pointed out that the fixed-price deadline expires in July, after 19 months. We have already been involved that long and progress has been sluggish. Although six months alone went toward obtaining the building permit, for which the GU is not responsible.
In any case, our impression is that we are being strung along, possibly to enable a price increase by letting the fixed-price deadline lapse. We have also contacted management, but weeks have passed since then and nothing has really happened. We cannot explain the GU’s behavior at all.

Today, I did some research and came across § 650k of the Construction Law (Baugesetzbuch), which has been in effect since January 1, 2018. It states that binding dates or durations must be specified in contracts for work. This is not the case for us. Even in preliminary discussions, we did not receive any time estimates even though we asked for them several times.

Who can tell us how to handle § 650k if no time specifications are given in the contract or construction performance description? The Construction Law seems rather soft afterward and only aims at the fastest possible completion of the construction project. Can we somehow use this to put more pressure on the GU?

What are you sampling so diligently? You are building massively, so there is still plenty of time (during the shell construction phase) It simply isn't construction weather to start now. What are you asking about on the phone? Is the company large? Big office or one-woman office? Basically, a general contractor only earns based on construction progress. Unless they start, they can't earn anything. In my opinion, a general contractor starts when the logistics are right, meaning they are ready to begin with the earthworks and bricklayers in order to start filling their own cash register. Does the contract not mention anything about the start of construction?

No, we are building a custom prefab house, not solid. We called once after waiting 3 weeks for a reply to an email. We still had points to clarify so that we could finalize our [Bemusterungswunsch]. But without a response, it can't go any further. The [GU] builds 180 houses a year, so it's not exactly small. If the [Bemusterung] had worked in February, the house setting date would have been in September. Now it's pushing into the winter... Unfortunately, the contract contains nothing about the start of construction or completion. Rookie mistake on our part.

We once inquired by phone after waiting 3 weeks for a response to an email.

You don't get far by email in the construction industry.

The general contractor builds 180 houses a year, so he isn't exactly small.

That could be the reason: they have too much to do.
Back then, I started a construction blog and let them know about it. They visited it regularly – and felt a bit pressured, at least there were phone explanations regarding their status.

The emails were also due to the fact that we transmitted information in image form. In mid-March, a sampling protocol with a surcharge list even arrived. We found almost 30 errors in it. Among other things, tiles were completely missing, sanitary objects completely missing, heat pump completely missing, ventilation was suddenly no longer present in the living basement contrary to the contract, etc. Since our correction list, it has been completely silent. For 3 weeks. No information as to why nothing is happening. And in July, without a fixed price limit, it is supposed to become 0.6% more expensive per month... Such a construction blog is a good idea. I am considering...

Such a construction blog is a good idea. I’m considering...

A construction blog also makes sense for yourself – it’s basically a construction diary where you can record everything.
Set it up, then a few posts, land purchase, selection of the general contractor, etc... and then the topic of waiting and communication shortcomings.
Then proudly send the link by email to the general contractor! ;) ...
Our seller, who then made it his task to follow our blog, immediately grabbed the phone and personally explained to me that this and that takes time, there won’t be someone on the construction site every day (solid construction) and blah blah blah. They were actually afraid for their reputation!