I want answers!!!!!!!!!!!!!

I've got Telkom router for about a year and a couple of months and it's been great, no complaints. However, recently I was charged a ridiculous amount for October and when I called the customer care number, I was informed that I took out a new deal in September 2018 and it has been dispatched. I am livid because 1) I did not take out any new deal 2) the cellphone number on my profile suddenly was different 3) what documents did they receive to verify that the correct person was taking this new deal 4) which address was device delivered to. When I got my router, Telkom got hold of me on the correct cell number. I want answers and proof. If this was an error from Telkom and my details were implicated in error, I'm going to sue Telkom!!!!!!