Sounds like your mechanic doesn't know what he is doing.
The 70 low and 140 high should have been a big red flag.
Normally, when you get low side pressure too high and high side pressure too low such as the readings obtained that means the compressor is in a de-stroked or in a no-pump condition.
Therefore, there is a high probability you have a bad compressor (internally) which may also be the cause of the leak.
For the improper vent operation you may have a bad vacuum line connection from the supercharger to the HVAC system or a bad HVAC climate control head unit.