Bloodsucking ticks

i bought a new car a few years ago and fitted a beame or carmatrix tracking device to it so that it could be traced in case of theft, The original contract was cheap and for 2 years. When the contract expired they started phoning me to extend the contract. One especially rude person phoned me and said that the contract price will be now 100% more than the original price. I flatly refused and started looking for a new supplier. I found one and then cancelled the Beame contract. It is now 2 months later and they keep on sending through a debit order every month to my bank. I do have reference numbers where I cancelled the contract but beame keep on regardless. I think that they are acting without integrity. I removed the tracking devise and also remove its batteries so that it is no longer operational. Please can somebody just do something to get these bloodsucking ticks of my back.