Affordable Locksmith Service Call

We are members of Angies, but I did not use the website to find a locksmith that day because I was not able to locate our password.   The deadbolt and door lock, to my outside shed were frozen and would not open .  I used lubricant, but it still did not open my locks.  By the time  the locksmith showed up the locks opened easily; however, the locksmith said that both locks were not operating correctly, and the locks should be replaced. I did not ask him how much it would cost  to replace both locks, and said that if both locks were not operating correctly, it would be all right to replace them. I am 84 years old and had not been thinking well because of two recent heart hospitalizations.   I have been dealing with honest workmen for many years, and did not think to ask him for the cost of replacing the two locks. He replaced both locks and presented me with an illegible bill for $662.  I felt obligated to pay him even though I thought the charge was unreasonable. When my wife called the owner and asked for an explanation of the bill, he refused to give an itemization of the bill  even  after repeated requests and was extremely hostile.  He did offer to settle for $500.00, but without any itemization, my wife refused that offer. The next day, a search on Angies list showed that the highest price for a similar service was $200. We wrote to the Better Business Bureau and asked them to investigate our complaint for an overcharge.  However, that business has not responded its letter asking for an explanation.  I estimate that we overpaid at least $400. .