A lack in admin support resulted in my harassment

The first account i ever opened was with Mr Price in 2012. I have missed payment by accident and rectified it upon realising my mistake (almost immediately). I was retrenched in 2014 and paid my account in full and then used it again when i found employment the following year. Fast forward to this year.... i was retrenched again. I went in to Mr Price to change my contact details a month before leaving my job (as i had used my work email and cellphone number to receive bills) I even had a policy with them which paid out to me when i notified them of my retrenchment. Everything was sorted i thought. About 5 months AFTER this, i still had no work (still don't) and then they decide to let me know i owe them almost R700. By now i have nothing. No money to solve this and they had my contact details all along. I told them this. If they had let me know off the bat which they should have i wouldn't be called and harassed and threatened almost every day! But to let an unemployed person who thinks their debt is settled, know months down the line is just pathetic. I am really disappointed and plan on paying my debt and closing that account all together as soon as possible.