absa harrasment calling over 4 times a day

ABSA has sent me a minimum payment that they currently require. At the moment, I can’t afford what they proposed; it's not much less than my normal monthly payment. I have communicated this to them repeatedly, yet they continue to call me multiple times a day—sometimes 4-5 times. I pay what I can every month, but they still contact me daily about the same issue. This is affecting my job because the calls come with varying amounts, and since I use my phone for business, I have to answer every call. It's also impacting my colleagues. I can't put my phone on silent or turn it off, and I feel this is harassment. I have reached out to them through WhatsApp messages and emails every day, but the calls keep coming.