Car wash goes wrong

Having joined Discovery recently after a very persistent effort by their salesman I was pleasantly surprised to receive an e mail stating I could get a free car wash at my local BP service station on the weekend. Arriving at my local BP I was promptly told by the couldn't car less staff that their allocation of 30 cars had been reached and I was turned away. Several other Discovery clients were being told the same thing. Need I say I was very disappointed at having my first Discovery carrot being declined as nowhere in the Ts and Cs was it mentioned that there was a limit. The cost of the petrol to get there and then resultant outcome leads one to wonder if all the various schemes one is offered by this company are of value. Message is be careful buying the product as I have been caught out in my first month of membership which is extremely disappointing.