MFC Nedbank trying to to me

Hi guys, not sure if anyone else has the same issue with MFC Nedbank but my account was in arrears and I made an arrangement for payment and there is a Lady handling my case but I was able to pay the full amount and tried calling her to cancel the arrangement but I it always says the number is not available, I then called collections and they said that I have to to speak to her. I tried many times after that but it's always the same and her number is not available. I just put all the funds in my account and waited for them to debit as I had no other choice. Today I received an email saying I need to Pay R806 again with the same contact details for the same lady and I've tried calling with the same problem exactly 20 times and each time it says the number is not available. I then called collections and they said they would put me through to her directly and still no luck, I was on hold for 5 minutes until I cut the call. I think it's absolute *******... I tried to contact her initially to cancel the arrangement but could never get through to her and now they want me to pay extra and when I'm trying to contact her I still can't get a hold of her. This will definitely be the last time I ever use MFC.