Cannot get my proof of payment

I bought my phone on contract at an 8ta store in Trade Route mall. I had to send my phone in for repairs this week at Samsung and I was asked to bring in my proof of payment to prove that my phone was still under warranty. The 8ta store is I bought my phone from is closed, so I called the new Telkom store at Trade Route mall and they told me to call the Telkom mobile at The Glen. When I called the Glen, they told me to call Trade Route Mall to get my proof of purchase. I called again and they said they'll get back to me. My phone will be out of warranty in about two weeks and time is running out with them giving me this run around. Who am I supposed to call for help? All I need is an email with an attachment that contains my phone's serial number and/or IMEI number.