Not reimbursing my money

This all started on 1 April and till today it has not yet been resolved. On the 30th February vodacom deducted R6510 from my bank account, unfortunately there was not sufficient funds and the bank returned it as unpaid. On 7 March 2016, I did an EFT of R6510. At the end of March Vodacom deducted 2 invoices from my bank account totalling an amount of 12590.95. After phoning vodacom on the 1st April, they informed me that the proof of payment should be sent to [Email Removed] I did that. They also said that I should phone *** after 2 hours. I then spoke to Lungile and also sent her the proof of payment, she informed me that vodacom will contact me and ask whether I want the money back in my bank account or whether I would like it to be credited to my next vodacom account. I informed her that I will need the money back in the bank as some of my debit orders went unpaid due to this. Now, thanks to vodacom, I have a bad credit record. I have contacted vodacom on numerous occasions (6) not counting customer service. I sent them an email again yesterday asking to resolve this issue, but still no contact from them.