MiX Telematics - Unlawful submission of debit orders, after debit order was cancelled more than 1 year ago

This is the second time in a week that they are UNLAWFULLY submitting a debit order against our account when our services have been cancelled with them more than a year ago. Our 3-year compulsory contract with them was done in 2018 and we cancelled our services with them last year during lockdown and we could not work and did not earn anything. They insisted we owed them this amount which is almost triple what our monthly subs was and we asked them in several emails to send us our signed contract with them so that we can see the terms of conditions - they ignored us - I have proof of these emails. They never sent the contract and eventually I ignored their emails too and in the past week they illegally and unlawfully deducted this amount from our account - I had it returned the first time and the bank insured me that amount was blocked for 3 months, but again this morning it was deducted.