Air con no compression but compressor working

Hi everyone,

I've got a bit of a strange problem with my Mk II 56 Octy.  I had the car regassed at a local F1 autocentre, it worked for about a day then nothing so I took it back and this is what they told me.

There is 5 bar in both the high and low system side

The scan confirmed that the the compressor is running at around 1000rpm but there is no compression of the gas in the system.

I then confirmed that there is gas in the system by taking it to Kwik Fit who confirmed that there is gas in the system and it is at the right weight of 525g.

So if the compressor is running but not compressing what is the problem, could it be electrical, any ideas?