Lizcole:
Don't have a lot to add to the previous good advice.
Couple of things. I would recommend you take a photograph of you meter showing the current reading and meter serial number before the "evidence" is lost if the meter is exchanged.
Secondly this might seem a stupid question but I want to be right on this, do you agree the meter currently indicates a reading in excess of 17672?
I don't think you mentioned the name of your current supplier. Care to name and shame?
I am VERY surprised that the supplier's billing system accepted the 17672 as a valid reading. Regardless of whether its right (unlikely) or not I'm really surprised the system didn't flag it as supect. Is that a meter reader reading or a customer reading BTW?
Once this issue is sorted as I expect it will be, I suggest you consider raising that specific issue as a complaint strictly in accordance with the suppliers code of practice on complaints.