Demand pmt 3 years later when i owe nothing after contract ended

So i had a dstv 3 years ago. It was on contract and contract ended and i cancelled put in wifi and i disconnect decoder not using their cservice. Now for the pass 3 months i get calls from laywers saying i owe multi choice R300 and odd coz apparently they let it still run for 2 weeks after no pmt was received. Now they want to say i had an contract. I contacted them before my contract came to an end and i was told if i cancel I will have to pay the decoder which i then decided to cancel after contract finished. when i told laywers that they asked me do i have proof. What **** is this you contact me 3 years later after i spoke to multichoice that time already and was under inpression it was all sorted. I dont owe them anything. This is rediculous.