Airtime not mine on Edgars Account

Since March 2018 I have been charged airtime of R70 which I did not opt for and neither does it get credited to my cell phone. I don't get statements so only realized this in October and gave since been battling to have this taken off my account and to be refunded. I tried to link my card to online access but it says the cell phone number Edgars has on record is not mine. Clearly ***** has taken place on my account. I am a pensioner and it is difficult for me to resolve this, I have taken it to the local Edgars in my town who spoke to H/O on my behalf for the third time on Thursday. They said my account will be credited and they will phone me to confirm this. They said it would take 24 hours so I should've heard on Friday. I had tried on previous occasions to have this sorted but with no success, so I am really becoming desperate. I also don't know why I never receive a statement so I never know what is happening on my account. I have a suspicion someone has linked their cell phone number to my account number and they have access to my account online. I was informed by Edgars on Thursday that a third party was debiting my account with airtime. How is that possible? I never gave permission and I don't even get the airtime on my phone.