4 years after construction, the office also demands land acquisition tax on the house

Since now a tied transaction can be seen, I find that quite extreme and would not have expected it.

You could have suggested to the seller to engage you in planning with a planner of his choice. That would have fully satisfied his purpose of avoiding construction with a lone wolf and prevented the tax trap for you. Or before signing the contract, you could have asked the tax office as a yes/no question to Radio Yerevan (it is not allowed to advise, but it is obliged to provide information) how it assesses the specific case constellation. A third way would have been to make a deal with the general contractor that he refuses to contract with you, and then be able to build with another contractor. That too would ultimately have broken the tying. Now you can only complain, but "mimimi" is not a tax law argument.

Your lawyer, who has thoroughly reviewed the contract, doesn’t say anything about that?

So the situation does not look good for me, I have now understood that. Thanks first of all for your input on this matter.

What I do not understand now: on which amounts would the real estate transfer tax be applied:
- All services of the general contractor up to move-in?
- All services of the general contractor until today? (Example: this year - and thus 4 years after move-in - I asked the general contractor to install an electrical line).
- All future services of the general contractor? Because I would like to convert the attic next year.
- On the VAT I have paid as well, or only on the net amount?

The question is, why did the tax office wait 4 years, until shortly before the statute of limitations… it could well be that the tax office is trying it once with the full tax. I would have a letter drafted to the tax office as part of an initial consultation with the lawyer.

What I do not understand now: on which amounts would the real estate transfer tax be applied:

You have a general contractor and yet a general contractor contract, right? Does it not state a construction sum for the creation of a portion of the house (of course gross, sorry)? I would state at most this amount, the tax office will probably also want to see the general contractor contract.

If I wanted to file an objection, I would contact a tax advisor and not a lawyer.