Warranty or guarantee case in the event of a defect in a turnkey condominium

Good day.

I have a problem with a tradesperson who worked on my almost 2-year-old condominium (turnkey purchase from the property developer). Now I am wondering how I should proceed. A concealed fitting is leaking after not even 2 years! According to the tradesperson (who installed this in this turnkey condominium), this is wear and tear. I spoke with the manufacturer. They say "clear warranty case." I have already received the invoice from the tradesperson.

Now I am asking myself
- Does this not fall under the warranty (5 years VOB) through the property developer?
- Does this not fall under the guarantee against the tradesperson (2 years)?

It would be nice if someone could clarify this for me.
I hope the information is sufficient.

Thank you very much

Defects that occur during the warranty period are submitted to the developer in writing with a deadline. -> Defect complaint The developer takes care of remedying the defect. You do not have a contract with the craftsmen, but with the developer. He is your contact person. He forwards the defect and the order to a trusted craftsman or arranges it differently so that both parties are satisfied.

What you do with your invoice? Whoever orders the music pays.

Of course, you can always try it with the [BT].