TV license harrasment

I paid my TV license via the public beneficiary option on online banking via EFT on the 28th of February 2018. I used my ID number as reference as I did not have my TV license number with me at the time. When a recovery agent phoned me I explained this to her and she asked me to mail my proof of payment to ********** which I immediately did. Afterwards, for 14 days straight now, I keep on receiving daily phone calls from the recovery agency telling me that I am behind on payment and after I explain the situation to them they ask me to email my proof of payment again. I did this 3 times now. Today I did not answer my phone as I was in meetings mostly, so they called by office to harass me about this matter. I find this totally unacceptable! I get no response on my mails to them and constant recovery phone calls that leads nowhere! I hope this will reach someone that will be able to assist me properly in this matter.