Alarm Con

Many years ago a subcontracted technician from either Chubb or ADT (later to become National Security so excuse the confusion) arrived to fit an alarm system. He offered to fit 2 external beams as as separate deal,payment via a debit order to FREE ALARMS . I naively/foolishly agreed to this and having being paying for years. When I recently tried to cancel the debit order with ABSA I was told (as usual) that they could do nothing about it ; I must contact the company myself and sort it out. There are two cell numbers and one landline listed for this company ; none of them are in operation. I have google mapped their address which is given 230 Vasco Boulevard ,cnr Vasco and Voortrekker , Goodwood and there is no such company visible. All efforts to contact this company have been unsuccessful . I dealt with someone called Jon Taylor. If anyone can assist me or give me advice on how to proceed, I would appreciate it.