Disaster

I have been with FNB for some time and I have never really had an major issues until last week. I lost my phone and have had to get a replacement phone. I haven't received my replace sim card so I am using a new number which is fine. The issue is that FNB debited me twice and when I went online to let them know they said I must go into a branch. When I got to the branch on Monday the 25th of June they gave me a phone to call their refunds department, when I did I just through to an automatic machine who asked that I leave my contact details and they would get back to me within 72 hours. I didn't receive the call after the promised time so I went to chat online where they told me they couldn't help me because they didn't recognise the device I was using to chat so they sent me steps to very my device, I followed the steps to no avail. Today I went back on chat they told me they were gonna call me and put me through to the technical support team, which they did. When they put me through to the technical team, the lady told me the only way to activate my device would be for me to pay someone R300 then it will be activated in 7 days, I explained to the lady that I cannot pay anyone because my account has no money do to the double debit they took from my account. The lady then put me through to the refunds department who were supposed to reverse the payment but they hung up on me before they even attempted to assist me. I am not too sure what to do now, please help.