Air Conditioner Trouble

I have a 98 Ford Escort with 94,000 miles. A few weeks ago, my blower motor went out while I had my AC running. When I brought it to the shop, they replaced the blower motor and the resistor, but then they told me that my AC needed to be recharged. This seemed odd to me, because prior to the blower motor going, the AC had been running fine and blowing very cold. I told the mechanic not to recharge it, but sure enough, since I picked up the car, the AC only blows hot.

Could something have gone wrong at the shop that caused my AC to leak and need to be recharged? Might they have opened it up for some reason? I didn't think they needed to do that to replace the blower motor and resistor.

I appreciate your input!