Impossible to get an invoice amount deducted

I need an invoice as at 1 March 2015 for an amount of R1 316.13 that has already been deducted from my account. As at 16 March this invoice was still not available on the website. I phoned the call centre to ask that they email me a copy of my invoice and received the following reference number: ***. I have not heard from them nor have I received an invoice. I have subsequently tried on numerous occasions to contact their call centre but it is impossible to speak to a consultant as the phones remain unanswered. I need a copy of the invoice as this is the only way that I can claim my cell phone expenses back from my company. I have done everything correctly and it is really frustrating that you cannot resolve such a simple query, which means that I am out of pocket. You are making it harder and harder for me to remain a client of yours.