Steelcraft Folding Gate Corp

I was recommended Steelcraft gates to repair my gate. I spoke to the owner who wanted $350 just to look at the gate. I explained that the other gate repair servics are giving free estimates. The owner consented to give me a free estimate. The repairman came to see the gate, but because there were boxes obstructing the motor, he has asked to remove the boxes and he will return in an hour. Before he left he had asked if he can sign the paperwork which he said just shows that he was in the premise and not that he has done work. I had signed but wrote on the bill "no charge" and "0000" under the fees. The repairman never showed up and I have been getting numerous bills and letters that I owe $350. The original bill has been manipulated and "no charge" has been erased. I immediately sent him a lengthy letter positioning myself why I will not pay the $350 and even if there was a miscommunication upon the free estimate, there was no estimate given because the motor was not even looked at. I am still getting letters threatening he will go to collection agenices if I don't pay.