Discovery Bank absolutely useless and ***********

Trying to pay into my Discovery card has been a nightmare. My old email is still listed on their system. I can't access that email due to it being a previous employer. I can't change my email and password profile because that email is inaccessible. After dealing with numerous service desk people to try and assist me, no one can assist me. Now they have handed me over to a third party financial collector to recoup the debt. How can I make a payment if you don't have a physical payment desk (like a bank !!!!) or your useless systems don't allow me to make a payment ? Shame on you !!