Unsrupulous People

i wish i can give -10 coz that is my rating for them. i took out a rent your agreement with Rental plus earlier this year. They were quite efficient and did the agreement fast, then they instruct you to give them a good review hence they have so many good reviews. Then last month my debit order didnt go off and i was instructed to pay my rental amount of R499 plus interest of R160 okay i thought maybe its fair and all. So the debit order was deducted for the amount of R659 no authorization requested or anything after they said i must pay the R160 via EFT which i thankfully didn't. I then saw this strange amount on my bank statement that i don't know of and reversed it. next morning which was yesterday Monday 03rd i received a threatening SMS, Whatsapp and email. FINAL REMINDER TO PAY R659 AS WELL AS R300 INTEREST FOR *****. and the message continues i need to pay it yesterday or return their merchandise or they will file a ***** case against me. i messaged them and advised i will make the payment but ill do it on the 7th. today they message me again and they message my reference i gave also. So last month interest was R160 and this month its R300 this is surely ******* and definitely not regulated. I am hoping i get advise here as to where to take this matter further. I will not be harassed and bul**** by ************ people. Don't do business with these people