terrible service

Good afternoon I am really disappointed with Vodacom service, my router contract ended around March and i was not aware this came to my attention after they deducted R621.99 from the initial contract amount of R400 and i called to cancel, they said i can only upgrade of which i did and never receive that router. i did the second upgrade and never received it also mind due they keep on invoicing me R621.99. today i was told that i should pay R1243.98 before they can cancel the contract. their service is really terrible. the other consultant said i must pay R1865.97 because for September. The router was switched off from 26 August to date, all along i thought the cancellation went through at last. ca somebody explain to me how to you invoice someone something they never used . can someone cancel my contract please. the number in question is ***