Take it back to where you bought it from and ask them to fix problem, if you try claiming on the warranty and they realise you had the fault from day one they might argue the fault was already with the car before the warranty cover starts (from when you collected the car) and refuse to pay.
I had the same thing when I bought mine second hand from a vw dealer, the warranty was with the dealer group not vw when I took it to my local vw dealer on day one thinking I just needed a regas they diagnosed a new compressor. When I tried claiming through the warranty company they looked at the dates when I reported the problem and said the fault must have been with the car before I collected it and they would'nt pay.
Had to take the car back to the vw dealer I bought it from and they had to pay and they would try to recoup their costs from warranty company. Big bill as others have said if you need a new compressor!!