Extremely Bad Service from Mix Telematics

I cancelled my Beame tracker on the 30th June 21, giving 30 days notice period, as i no longer have the vehicle. The debit order went off on the 1st July and on the 2nd August which is fine. Debit order continued to go off monthly after being told that it was cancelled and would not go off again. in September i reversed the debit order, in October they tried to take the debit order 2x 2 Oct and then 13th Oct21. I am now receiving threatening letters, continued sms's to pay, after i've sent countless emails. I get no response from anybody there!! I was with Mix Telematics for 9 years and they are hassling me for R155 that i don't owe them...i find this very unprofessional and in bad taste. This is a last resort!! Stop harassing me and clear this account, thereafter please take all my details off your system as per the POPI act.