Rent King

I did a walk in to the store about 3 months ago looking for a few things for my apartment I found a bed set table and sofa that was on sale for 800 they told me 90 days same as cash so I am on a fixed income for being disabled by social security system and I have been making regular payments of about 286 per month so today I called to see what my pay off balance was and they told me 1500 + dollars I am very up set so I asked why is it if I have 90 days same as cash they told me my 90 days was up on 11/05/2016 which today is 11/16/2016 so I asked why was I not made aware of the date of 11/05/2016 when I did not pay over the phone this month on 11/01/2016 I walking in and paid in person a member of management took my payment and he never made me aware turns out that was the same manager I was on the phone with he told me that it's not his job to make me aware of it because that's how they make there money by adding interest to my account if I go pass 90 days then he said it's just like a credit card if u go pass the date u pay interest but my point is this is not a credit card this is a bill that I have to pay if I don't they will come take all of the stuff back out my home or if I don't give it back I can be jailed for not returned stuff as to a credit card goes on my credit I thought they were account Representative for the consumer help us to get things paid off now I very hurt and stress