Conns / deception on no interest payments

I bought a tv at conns for no interest if you make minimum monthly payments. I was offered to skip a payment with no penalty so i took it. my last payment was due in november, but because i skipped a payment i still had a balance due. i thought the skipped payment could be paid in december. i paid what i thought was my last payment. i called conns to check to my balance and to my suprise my balance that should have been zero was over $900.00 . i called conns and was told rather rudely that i should have read my contract, my balance had to be paid by november 17 . this is decpetive and dishonest .