Poor service and bad ethics

The unit stopped work soon after warranty expired. When I phoned them they said I need a lifetime maintenance contrack at R30 pm and they will fix the unit free of charge. This was concluded over the phone. After 2 months of the unit not working and nobody contacting me to arrange repairs, I tried to cancel the unit by way of e-mails and phone calls. They refused to cancel unless I completed a form. I completed the form and e mailed it back. It was no 4 monthes I had been paying for nothing. I cancelled my debit order as I was still beeing billed and got no feedback on the form submitted. After cancelling the debit orders, I now get threatening e mails stating that I have defaulted on payment and legal action will follow. Eventually customer service cancelled the maintenace contract and sent me a cancellation account for R500 +. How do you have R500+ penalty on someting that has a R30 per month subscription. None of this was explain on e mail or origanal sales call up to now. Beware of this product and how they do business.