Wrong shower tray installed without coating

Hello,

we have the following problem. In the quote from our plumber, we had a Kaldewei Superplan 90x110 with Secure Plus and carrier, which was supposed to cost amount X. Later, on the advice of our plumber, we changed the dimensions of the shower tray to 100x100. Now we have received the final invoice. I noticed that the item Secure Plus is no longer listed. When I asked, he also told me that he installed the shower tray without Secure Plus. However, the price is the same as in the quote. He offered to coat the shower tray afterwards. I do not think a subsequent coating is nearly as good, because with Secure Plus the anti-slip coating is baked in. A subsequent coating must be renewed regularly, right? Is this a defect? Or how should we assess this? I have checked online, and the MSRP of the shower tray with coating is about 500 euros more. Should we live with the subsequent coating? Agree on amount X, which he might be willing to accept? Or insist on an exchange?

I would have them exchanged. Just because of the statement that the price is the same...

Were the answers in the green forum not sufficient?

Were the answers in the green forum not sufficient?

I only posted here first and then thought about posting in the green forum

First posted here and then thought about posting in the green forum

... and have to endure the usual suspicions. It's quite funny that it basically comes down to a checklist approach where YOU (of course) are completely to blame and responsible. There you basically can't make inquiries unless you are a "construction expert" yourself and submit a corresponding sworn affidavit confirming the involvement of various experts.

I find the atmosphere there quite bad.

Yes, I also filter the answers. Usually, you are first to blame yourself, and if you have made an effort, it is rubbish. I just wanted to know which direction the tenor goes there. PS: I don't like the atmosphere there either. Apparently, there are only a handful of people who give a (correct) answer that is accepted there. The rest is doubted.