Vodacom Wifi dissapointing me.

Hello Peter. I am not happy with the Wifi Vodacom is providing me with. I have a contract with them for 70 gig day and 50 gig night and I am paying R499 per month. I also have a laptop with them R250 so monthly I pay the R749. My issue is the Wifi that hardly works when I need it to. I cannot hold Interviews and meetings at the house because I am afraid that this wifi is going to dissapointed me and I will lose what ever I will be doing. I have even had to buy more data from Cell C as back up for this Wifi. Now I have been trying to cancel this contract for a while and I get quoted ridiculous amounts of money. The last quote I got the amount was R6058 this amount is twice the amount I would have paid by the time I am finish the contract. The contract is ending in the next six months and the amount is about R3150. I am not sure why I need to pay so much if I am canceling and never to use it again. I would not need to cancel if I was getting quality wifi for the amount I am paying. I need to know why I need to pay so much to cancel or they better make sure this Wifi of theirs is working.