HAND ME OVER FOR PAYING?!?!?!?!

I had tests done in last year, funds being exhausted I started making pmts monthly to Lancet as I have always done (I over paid them for several months a few years ago that they had to REFUND me). I soon got threatening messages, saying i would be handed over should i not pay the outstanding balance. I promptly Called LANCET saying I cannot afford the total amount straight away and would continue to pay x amount on a monthly basis. this was agreed Upon. the next month i got the threatening message and once again i was on the phone to LANCET i was told the agreement was not logged on the system but they would make a note this time around. the following month AGAIN- Payment made THREATs RECEIVED! I then made another call i was told the system is automated and i must ignore the messages they can see i have made payment so it is fine. i then another message, i sent an email on the 29/03/16 this was responded to by Adrian Kruger *so generic - did you even look into my account?* On the 1st i received another threatening message once again i responded on email and got a reply from Christelle Naidoo *generic AGAIN* today you people handed me over *** sort this out ASAP CLEAR MY NAME