Edgars keeps calling to pay!

I am is disgusted with Edgars and the treatment I have been receiving. I paid my installment on time. I have since then been receiving nothing but rude and threatening sms' to pay. After sending in proof of payment numerous times and requesting an updated statement and for the calls to stop. I received a legal letter demanding payment. I then once again sent proof of payment. Still to this day I have been receiving nothing but calls to pay and rude sms' saying I owe them money. After several attempts to contact them via different platforms, I have had zero response but instead more sms' to pay. I am honestly so disgusted in this treatment I am at a loss for words.