Telephone service sucks

I'm trying to authorise my credit card for international usage.<br> I have tried to phone 5 times, each time I have to go through waiting , re-explaining, getting put through to an automated system, that after giving my details, asks for a 6 digit merchant number.. what is that???<br> Im getting no where.... and this means I'm going to have to go to the bank to try sort this out.... <br> Why is this process so difficult??? with Diners it took 3 minutes... and done.....