Unable to make payment

My previous employer was making payment for my fibre, I have since left the company however everytime I have to make payment I'm being asked for the reference number on the bank statement of my previous employer which I obviously do not have and I'm left without connection for days on end until someone goes a little extra mile to understand what I am saying. I am without connection yet again and yet again I'm explaining the same thing to yet another consultant who is not interested with my issue. And now i am unable to get a hold of anyone cos the call centre sends me to WhatsApp and WhatsApp support is not available