***** on my account and MRP Help centre refusing to assist

I opened a new MR Price account in June 2017. When I got my August Statement I noticed that I'm being charged for a top up SIM. I never took out any phone contract with MR price (top-up or other) nor did I ever bought or received a SIM from MR Price. When I raised the query with the MRP Help to investigate I was told sorry they can help me I need to go back to the store to sort it out. I then asked if they can at least provide me with the store contact details so that I can query it with then either by email or on the phone, I got a response no I have to go to the store. I cannot see why I need to go back to the store if all their records is supposed to be online, and I do not have the time to go all the way back there to stand in a queue and then have to explain all of this over and over again to someone, then have to sit and wait for who knows how long while thy try and find a contract or papers for a contract that does not exist. This is a ********** transaction on my account and I would expect them to investigate and if they do find something, any kind of documents, relating to this that they want me to verify then I will be willing to go to the store to verify. But I do not have the time to sit there and wait while they try and find this.