Sellers lawyer won’t answer

[Patricia Bustamante]

My parents agreed to put a 5% deposit on an apartment in the same condo complex we live in 5 days after the inspection report was issued for said property. However, the inspection report shows items that need fixing in the apartment, namely the HVAC units of which 2 out of the 3 units in the apartment don’t work.  The inspection report said they need to be fixed or replaced.  Upon the findings in the inspection, my parents decided to hold the deposit and not submit it until the seller agreed to fix the items in the inspection report, particularly the HVAC units. Additionally, they stated that they wanted a well-known private heating and cooling contractor who’s office is in the building and is well-versed  on the particular HVACS in the Condo complex  to be the ones utilized to check the HVAC units and give his opinion as to whether they need to be fixed/replaced and what exactly is wrong with them. The seller agreed to fix the items in the inspection report but has not responded to use the said contractor.  It’s been 1 week since my parent’s lawyer sent the statement to the sellers lawyer that my father agreed to submit the deposit if the seller agrees to fix the items on the inspection report as well as use the specific contractor and the sellers lawyer has yet to respond. My parent’s lawyer reached out again today but still no response from the seller’s lawyer. What could be going on? 
My parents are 70 (dad) and 77 (mom) and my mother has just been diagnosed with emphysema, and has had COPD for many years.  She just recently got out of the hospital with pneumonia. Therefore, the heating and cooling units in the house are of utmost importance. They only have about $30k in the bank and the deposit is for $14,400.  It would be heart wrenching to see them lose that money on a breach of contract.  What are their options?