not updating account keep sms and call i owe money

we have changed our bank details in November... they didn't deduct the premium end November but did in December for nov and dec... I am still receiving calls and sms saying I owe money to them... the money went off on the 28 dec for the month and the o/s amount... I have spoken many times to the collectors department and explained they said they will follow up with netstar and close that I even asked if I could send them the bank statement and the still said no it woun't be nessacary... that it will be fine and they will close it on their side as I am up to date... this is a problem as they don't do their job.. and it is imbarrasing if they phone to say you owe money if you don't at a work place as *********** people are not doing their job correctly and we pay for the service and they can't even locate your vehile... my husband numerously pressed the panic button to test when the installation was done and the don't even phone.... and cannot tell you where your vehile is then to top it all they only work office hours... this is phetitic- star4908 barnes account