Frustrated with African Bank

<p> I have two accounts with African Bank since 2010 and due to my circumstances changing I was unable to make payments on my accounts. I have since been contacted by DMC Debt Collection regarding payment of these accounts. I made my first arranged payment on the 27.10.2016 and have now been contacted by Mr Du Plessis who is calling on a private mobile number saying that he is acting on behalf of African Bank. He wants me to sign another contract stating that I am in going to make payments and if I don't sign the contract he has threatened to garnish my salary. As I have made arrangements to make payments on this account it is ********* for African Bank to contact me in such a manner. Further to this, Mr Du Plessis who claims to be acting on behalf of African Bank did not explain why he was given my details to contact me as I already made arrangements with DMC. He was also very rude and didn't explain why I needed to sign another contract. Is it so difficult to finally make payment and then be harrassed by different individuals for an account when all I am aiming to do is try an resolve my debt. </p>