Disgusting service!!

I arrived in the UK on Tuesday 29 December and have had nothing but trouble with my Cr card! I had the card opened for international use before I left. I tried to use it on arrival but it was declined. I called the Cr card division and was told that I had a pin hold on the card as I had used the incorrect pin. I am not a *****. I know my PIN number!! The following day the card was fine but the next day it was again declined. Once again I made a call and was given the same message. Both times I was told the card was opened and could be used. Yesterday I went to pick up a hired car and AGAIN the card was declined when trying to pay the deposit. Besides this all being very embarrassing it is ruining my holiday! I am here to be at the birth of my first granddaughter and now I have no money!! I will most certainly be changing my bank when I get home!!