Prime Appliance Repairs

I understand that they have a $79 drop in fee. If you agree to get the repairs done, they say they deduct the fee. My question is if the repair man comes over and charges the fee, when he returns to fix your appliance (because the parts are out of stock), is the fee deducted? He wouldn't tell me the cost of the part. I've heard of other companies pulling a fast one, with this drop in fee, then saying they'll deduct it if you agree to the repairs. They can tell you it costs so much and you'll never know. Does Prime tell their customers how much the repairs will cost, so we can deduct the drop in fee from the amount? Thx