Terrible **** on returns

I moved houses and had to terminate my contract with WebAfrica since they couldn’t be the ISP at my new place. On the 11th of December they send me an email about a 20 day return period for the router. Mind you that’s 9 days (I’m away) before I have to bring it in. And now they want to bill me R2000 for this LTE router. That’s proper ****, I won’t be paying this amount