They failed a part of the job and it was my issue to resolve with them. Document everything. Make sure you specify a penalty for not finishing on time or they will let the contract go on forever if it benefits them.
Had this guy build my deck in 2010 and it started falling apart after just a few months. Made one effort to fix it, and when he realised that it was a major job, he disappeared. Tried calling him but no reply. I'd be very careful before hiring him.
Did a decent job on the renovation, but quickly disappeared when problems started to show up. Not the kind of guy you can trust! Protect your money and hire someone else.