Suspected Theft of my Data

I subscribe to rain unlimited 4G with 1GB for use between 6pm and 11pm. 28/02/2020 I contacted rain via their online chat. I advised that I had lost my SIM and would need a new sim and the old one to be cancelled. They very promptly responded and advised that had been done and new sim sent. Delivery was scheduled for 03/03/2020 I was very impressed with that service. Little did I know what was to come... 01/03/2020 I receive an email stating that I have used a majority portion of my 1GB "Peak Hours Gig Limit". Now this is physically not possible as I had cancelled my old sim and the new one had not yet been delivered to me.

I contacted Rain for an explanation. Until today and many many emails later I have not received a response from rain addressing my concerns.