10 day inspection period; seller refuses to make repairs

[Michael Henry]

Would like some advise here I’m under contract for a quadraplex, during the inspection period I had a property inspector find a few issues, damage to the ceiling from a prior leak , safety issue with the stability of a staircase , and mold in the laundry area. These were the major issues in my opinion. A contractor quoted $3500 to fix these issues which may be a bit high , but the seller came back and said he would contribute $500 to repairs. Is this something I should just deal with and fix myself or back out?

Backing out would cost me $900 for the appraisal I already paid for plus $525 for the inspection.

On a side note the roof was replaced at a cost of $6500 2 days ago at the sellers expense.