Next time go and see Bernie at CTS his box's are simply the bollocks and he doesn't fob you off. I had similar problems with a recon box that broke and was told it couldn't be repaired under warantee as the car was modified, it had a fucking induction kit on it when it went on the rollers for the first time it only made 119bhp

This garage clearly don't know about the cars or the parts so it might be in your intrest to find a garage that knows what's what