Unhappy customer

I am a very unhappy customer at this stage,so last month I downgraded my package to the lower one and have always made payments on the 15th of every month.This morning I received an SMS that my services have been disconnected like how because it was only the 15th today.I phoned in and the agent says to me they did not receive payment and it's only 10h00 in the morning,if it was the following day I would understand because I would not have honored the payment. The agent insisted that I should still pay a reconnection fee and it will be reversed with Jon 7 to 14 days,how do I do that since I'm not at fault here.