The weather was horrendous on the night we landed at Newcastle. On leaving the car park we got a message stating we had not paid enough & I was to go to a pay machine. I had paid up to 1am & knew I had paid enough to cover the duration. There was a queue of cars behind me that needed to reverse - I located a member of staff, in the soaking rain, and was told in a matter of fact manner that the machine had not recognised my car ref number - he did something on a machine & advised the barrier would now let me out - I then drove home soaked through - not happy