Netstar a rip-off

Netstar is a ******* tracking company. Towards end of October a consultant called to tell me they need to install a new tracker, as the existing tracker battery might have worn out., And they will then continue to debit my account with the same premiums. To my surprise a debit went on the 27th as per our agreement, but when another debit was done on the 1st November, they told me it's a new contract when I enquire about since they have already debited my account in October why a second one on the 1st of November I told them I'm reversing the second debit and cancelling the whole contract as no installations has been done yet. To my surprise they are now threatening me with legal processes for not having paid them twice🤔