2007 SUBARU OUTBACK User Comment / Complaint

I purchased the car in february. up until late may, the air conditioning system was working flawlessly. it then started blowing cold for about ten seconds and then warm for five. this problem causes the cruise control to behave erratic, the transmission to shift erratically and the engine to surge because the compressor is engaging and disengaging. i have had the car in for service for this issue four times. the first three diagnosed the problem as overcharging of the ac system. the last one i was told this was normal operation (but why just all of a sudden start at 4000 miles?)