2slow

iTrader: (5)

Get a second opinion from another mechanic. Preferable a dealer.

Could be air in system and the "mechanic" didn't top off the fluids. Or worse.

Diagnose it yourself. Fill the master cylinder resevior to the top and pump your brakes x1000 times. If the level is low, and no fluid from lines or caliper, then you have a internal leak. Most likely fluid is leaking into your brake booster.