Maybe you just got the wrong perso.n on the phone ( or I did! )
I ordered something online from the US with my UBS credit card. The company kept on delaying the sending of the goods, so I phoned UBS and they cancelled the charges without any problem. As an added safety measure I also cancelled my credit card and ordered a replacement from them.
I also had to have charges disputed on my UBS credit card, and they were very efficient. They sent a form to me, which I filled out, and then they sent a second form that I had to sign (an affidavit stating that the charges were fraudulent and that I had not given my credit card to anyone). While this was all being worked out, I only paid the charges that I wasn't disputing.
Does sound like you got a rotten rep...