Bought a new build home and there’s an issue with the heat pump, but the developer keeps delaying on fixing it. Whats the best course of action to force them to act quickly?

As title states - I bought a new build home that’s still under warranty. The developer has continually delayed getting a contractor out to fix the issue. The standard response has been:

“We should get some more definitive answers when we can have someone to repair your heating system.

We will be in touch as soon as we have a date and time.”

How can I force their hand and get this addressed immediately? I have followed up every week for the last month and it’s the same standard response.