FNB wanting outstanding money from almost 2 years ago

I bought a laptop through FNB over a 24 month period. My last payment was due in April 2017. I got a call today saying that I still owe an amount of R685 for this. It is almost 2 years later and only now do I get a call form FNB collections saying that I owe this money. When asked why I was only called now and knew nothing about this prior to today - the lady on the phone told me that FNB only implemented a collections dept in Oct 2018 and they are going down the list. I actually find this disgusting that FNB has not contacted me for almost 2 years and now they are hounding me for an outstanding R685. Seriously??!!