This caller is actually ACM Group, it is not generally known but they are totally owned by Telstra and their premise is to collect any outstanding debt to 10 years old. Do not take them seriously, in the case of a 6 or 7 year old debt they have absolutely no power and they are not taken seriously even by courts. The reason that they are persistent is that they have completely free telephones and they are only paid a commission.

They would not give me company they worked for just Mary from Sydney, Australia.

ACM debt collection, Sydney based

It's a debt collector called ACM Group

It's regarding an outstanding Telstra Mobile Phone Account

This caller wont give any reason for call, and almost give me a heart attack. I will report them to the Police if they keep calling.