Can you tell how much was the high side reading and the low side reading.
High head pressure in your case might be refrigerant over charge but only if the low and high side pressure readings are above normal range as per temperature pressure chart for R134a. If this is the case evacuating extra refrigerant can bring the readings in normal range.
One more likely reason may be too much oil in the system as the ac technician dont know Sh*t about measurements.
If the TXV is sticking close causing blockage the high side pressure will be huge but low side might even get to -ve (vacuum) with slight increase in rpms.
Dont forget to wear protective glasses while you stand by and monitor all this as pipe joints or valves can pop at abnormal high pressures.
Get your car back to Ahmad Car AC (Babar) and tell him to rectify. Keep up the pressure on him and tell him your engine got overheated coz of this with an extra 3K for the head gasket etc etc.