Terrible, non-functional service, communication and billing

Absolutely terrible service. They don't answer calls, their agents are rude and unhelpful, and their WhatsApp chat is non-functional. I contacted Cartrack with a number of queries regarding my contract and services which were never responded to, and eventually cancelled my contract, which also took several weeks to coordinate thanks to their poor service. Today I get a WhatsApp saying my account is in arrears for a strange, small amount, even though they processed my final debit. I reply to them asking for clarity and get a response two hours later simply saying "Your account is in arrears". No explanation, no formal letter - nothing. And they do not respond when you try to proactively contact them. Still waiting for more information. Cannot wait to be rid of this awful company.