Calor Think Tank - inapproriate filling

Hi,

Has anyone with a bulk Calor Tank and the calor Think tank telemetry unit had problems with Calor always filling the tank just before your monthly payments are reviewed?
They have done this to me for the last few years, this year I still had over 40% left in the tank so really didn't need a fill up!
They (Calor) say it is just coincidence but I think not - it seems a deliberate act to make you either pay a lump sum to clear the balance or increase the monthly payments by a much larger amount than required.
Before the unneeded fill I would have been nearly £300 in credit by renewal date, now I'm looking at owing them nearly £200!

Needless to say I have demanded the telemetry be removed so the gas deliveries are in my control not theirs.

anyone has similar issue?