Unacceptable service - I cant understnad why Discovery Bank uses them?

I ordered a bank card through Discovery Bank. A few days later, i get an sms saying they've tried to get hold of me unsuccessfully, but there are no missed calls and my phone has been with me. I then finally get a call from them, and when i answer it - it's an automated message saying they couldn't get hold of me! This is bizarre, they've gotten hold of me with this bot, to tell me they can't get hold of me. When i tried to phone them back, a few times, it is impossible to have somone pick up the phone. You're told there is high volume of calls blah blah. I then phone Discovery, and order the card again and reserve a time for delivery. The morning of the delivery, i get a call from DSV, asking me to book a time for delivery. No clue that it had already been reserved. THe woman says, no problem, it will be delivered at the specified time, and she'll call me to confirm it came. I got no delivery, and no call from the agent. I again phoned Discovery and all they could do is book it again, at another date. I don't know why Discovery, which seems to be interested in customer service, are using this dismal company.