calling me twice everyday harassing me for payment

agents are calling me twice a day just to make payment arrangements for one account even if i did arrange they still call me non stop, telling me that i refuse payment but they deducting every month more amount than what we have arranged for. all agents i spoke to are very rude. my credit card account was handed over to MCS debt recovery but still African bank wants to also deduct. All i need is for this agents to stop harassing me with all this daily calls they must just update their system and wait for payment that's it.