IS IT MY FAULT?!!

I have been trying to apply for a store card more then twice online and it was a success(twice). But when the call centre staff calls me to process my application they keep saying that the system is rejecting the postal code. On the system when I apply it gives a ZERO (0182) but when they process the application it does not give them a ZERO, just 182, which is wrong by the way. Two different people took my number and promised to call back but they never did (typical) and the third person just said sorry I cant help you and dropped the call, WHAT?!!. I am failing to understand how I can resolve this at my end because I did not create the online system, they should know how to use it. Why is this my problem now?