Home Improvement Questions? Ask a Handyman for Answers
I know this doesn't answer your question but I am asking you to listen for a moment. You don't fix it! You have him or her fix it. Since when are you responsible to repair an obvious flub by your contractor. Is he licensed? Call the building inspector if he doesn't respond and is licensed. You hired him and he has a duty to perform professionally and is liable to make things whole for you. No contractor worth their salt would leave a person hanging with a bad job like that. Your contractor didn't do his/her job. I hope he/she hasn't been paid yet, If so, I hope you learned a valuable lesson from this. I hate bad contractors, I used to make my living going after them!
Sorry for your bad experience :(