Integrity Roofers

I hired Integrity roofing (through *** and with dealings with ***) to reroof my house. They did the reroofing. We had some disagreements about the colour of the metal work, we agreed I would pay 500 dollars extra and they would redo it; I paid the full of the roofing cost as agreed in the contract. They then fixed the down spouts and I paid them the agreed $500. About a month later I realized there was exposed wood left on the side of my house; I complained to the company, they fixed it and started sending me a bill of ~282.50 (the latest time). I never agreed to pay this fee and would not have. they should have covered the exposed wood in the original work. I have tried and tried to call and email the company and to contact both *** and ***. They do not return my calls and emails but keep sending me a bill. I do not owe them this money and want them to stop trying to bill me. I also want to make sure this doesn't impact my credit.