Harassment and now ******ion

i have been called and messaged by mbd to pay my tv licence acc which I did on the 25th of july and still they are phoning me till today still .They called me 04/07/18 to say I did not pay and then mailed then proof that I paid to ********** as advised by the consultant on the phone , then again on the 05/07/18 I get a call and I send email to martin magosi ********** and on the 20/07/18 to show that I have paid and that im due a refund since the consultant misinformed me on the amount ,the amount due was R344.50(I have the sms as proof) and I paid a R370 on the 25/06/18, I still get calls saying I need to pay and every time have to explain and tell them I mailed the proof of payment then on the 19/07/18 I get a sms to say that I need to pay R371,i then queries why R371 since I did pay them and yet again I still receive sms and calls saying I did not ,now today 14/08/18 I get a call again saying I did not pay and that I need to pay R391.50,i ask if they can see that I did pay R370 they say yes they can see that but I still need to pay the R391.50 when asked why they can give me a answer .Please I need help in resolving this issue as this Harassment and now ******ion can't go on