Theft of payment by vodacom

Got my latest statement, and I noticed that the payment I made on 1 March was never deducted or marked. Just paid attempts to contact Vodacom or impossible. The CEO doesn’t respond. He just leaves it. I want my money back and I wanted to sort it out I sent them an email with proof that I paid them, and they had carried it over to the following month. Somebody needs to get involved who will help me here