Follow up from before

The whole bathroom is almost complete. Finally. There are still some details that need work, but otherwise it's finished. The one funny thing about it is that the contractor wants more money than he originally said it would cost. What right does he have? He took 3,5 weeks longer then he promised, made hundreds of mistakes he had to correct, we even had to buy some tools for him! We provided all the materials and all he gave was his work - rather poor work at that. Really, this guy has the nerve... I'll be happy to be rid of him as soon as humanly possible, never to see him again.