Services unusable and call centre is rude

Hi,

I have a card with this business which I am unable to use at the stated retailers. I called more than 10 times and it's no help because the staff at the call centre are rude and unhelpful. I even asked to speak to a supervisor/manager and was told they don't escalate calls where someone got bad service from the call centre. When I protested, the lady put me on hold for 6 minutes and I eventually gave up and hung up.