Paid made in January and getting calls daily

I changed banking details in January 2019 and informed Finchoice accordingly. The person advised me to make an eft payment for January which I did on the 28th of January 2019 with an amount of 2426.49 and the reference was my I'd no. After that I have been getting calls on a daily basis. Explaining the same story over and over. I was promised that the back office will allocate my funds but this morning, I received another call. I mailed the proof of payment to ********** and it was read on the 7th of February 2019 at 9.06am. What can I do more? I want to feature my story on Carte blanch maybe then Finchoice will wake up and smell the coffee.