Please help

I have a loan with capitec that is due to be paid up in Feb I missed a payment one month and have been making arrangements for it to go of a month later than I am suppose to be done with it. I had a call from a consultant in the week who informed me that I can't make month to month arrangements anymore I must this month pay double or pay extra. I explained to the consultant that I was unable to as I have had an operation and I am going back in as the original one was not a success which means that my salary for December won't even be enough to pay my origanal payment but it's like they don't care at all. Capitec is worst than the bloddy Cancer they removed from me. I don't know what to do as I won't be able to afford what they want