Can’t buy a house

I have been trying to buy a house that has Sunstrong, but before we can close we need the solar transfer to go through. We have been waiting for weeks, even after paying for expedite fees. We had to push back closing and I now have to pay a $1200 extension fee for the loan terms. The owner and I as well as: our agents, title company and mortgage broker have all tried calling and emailing them everywhere we can, but nothing has gone through and we haven received any actual help. Waited on hold one day for 2.5 hours and when I explained to the rep what was going on they hung up on me.