R16k bill for 3 numbers that aren't mine

I've been billed a little more than R16k this month, of which, 3 numbers listed on my statement, aren't mine. I'd appreciate a phone call from a regional manager who is able to resolve this and credit me immediately. This is totally unacceptable. My bank account is currently in overdraft which affects my credit rating. I'd like a letter of apology to submit to FNB aswell, to try and resolve on their side. I trust this will receive your urgent attention. I'm in meetings for most of today, please contact me after 5pm or email me with feedback. I've tried your \ customer Care Call Centre "twice aswell"