Not helping adding too much strains to my finance

I have a huge problem with a game consultant who calls me 3 times a day informing that my account is in arrears due to the short payment I made. I have informed them that I cannot afford the amount they want me to pay. I'm on a financial strain but with them calling me more than once a day for the call I am paying for is not helping me. It is not that I am not paying my account I am making payment and yet they still bombard me with calls every day when my statement comes I am being charged R24 for all the calls they made whereas I have advised them I can't afford the amount they want when I can I'll pay it . and the consultant has the nerve to tell me when am I paying their money?