Unauthorized debit

I have since discovered on my bank statement that a company known as a digicash have been debiting my account without my authorisation.Upon investigation they told me they debiting for a company known as Primax Communications and they provided me with their contact numbers.I have since then been speaking to this people and they acknowlwdged that they do not have any business with me and will refund my money back.However they still have not refunded my money and I am now waisting more money on airtime trying to get my money back for something I do not know.This is unfair and unacceptable that I am the only one waking up very early in the morning going to work and someone else just take your money without shedding any sweat.In fact it is b****** and I want every cent including the debit order charges as a result.