DAY LIGHT *******

I just want to know this please help me understand??If i take a TV from them do i pay interest every month?is this like a Loan?or am i missing something?I took a TV from them which all in all came out R16 605.50 so i have been paying R778 since September 2021,March 2022 i started paying R1000 So tell me if my calculations are wrong.I paid R8 668 in total my BALANCE should be R7937.BUT they say i owe R11 253.66 how on earth can this people not count???or am i the crazy one?where is all the extra money i am paying???i am going to take this matter further imagine...the TV was actually R11 000 but with higher purchase it is R16 600..I WILL NOT RECOMMEND THIS PEOPLE TO ANYONE.So what they are saying is does not matter even if you pay extra 36 months is 36 months?*** so where is all my other money?????