My Duplicate Payment Nightmare

I contacted Xecutronix (via phone) on the 5th of August to enquire about the price of replacement remotes for my LG TV. I spoke to Mpumelelo Mashigo, who emailed me a quote for two remotes, amounting to R1066,35 on the same day. On the 19th of August, I paid for the remotes. However, the payment was duplicated due to an error on my banking app. The bank said they could not reverse the payment because it was immediate, and that I'd have to contact the company I paid to reverse the payment. I notified Mpumi about the mistake, and he rep**** on the 20th of August, saying he would order the remotes and notify his Accounts Department about the error. I haven't heard from Mpumelelo Mashigo since the 20th. I emailed Mpumi again on the 28th of August, but he hasn't rep**** to my mail. It's been over a month since this happened and I am unhappy with this situation, especially with the lack of urgency from Mpumelelo. Someone at Xecutronix gave me the contact details of their boss, Clinton Jansen Van Rensburg. I have called and emailed him, and he is yet to reply. I also contacted LG directly to notify them about my situation, and they have shown the same urgency as Xecutronix have. I'm frustrated and no longer know what to do. BE CAREFUL WHEN PURCHASING LG PRODUCTS... AFTERSALE SERVICE SUCKS !!!!