Call Center needs training!!

I had called the Nedbank call centre on the 03.02.2016 on *** I was thereafter transferred to *** and thereafter transferred to *** to inform them about my account being paid by a mediation company. I was holding on for 25 minutes and no answer I called again today and there was no answer. Today I received a call from the collections company asking about payment after I have tried numerous times to inform them of the payment arrangements especially after me trying to inform them of these arrangements . Another thing is that you are never asked if you are available to talk, I work in an open plan area and the first question that you are asked is to confirm your ID number and not if this is a convenient time to speak????Is the number *** even in existence?