Cancelation fees

Wow! So i signed up with Vox... which went well untill i missed a few payments due to financial reasons and i am also unemployed. Long story short. They cancel my service without me (bare in mind i did not want to cancel. I was planning on paying up and reconnect) i was owing for about 2 months. They send me a invoice of R2000 some odd for cancelation fees... so this morning a month later... another invoice over R4000 . Its literally Worse Then Rain ...the worst worst internet service ever making money off ppl. I am so sorry i will not pay such fees!