Cancelled my services and still being debited!

I cancelled my contract in January 2018, have an email stating that my services with Neotel will be terminated on the 7th February 2018 and that a technician will collect my antenna and modem on the 10 February 2018. All went according to plan, internet switched off on the 7th, technician collected equipment on the 10th and signed it all off but guess what, i got debited now for the month of March? Can you explain to me why? How do you *****s operate? I will be taking this further should i not get my refund!