VODACOM IS FRUSTRATING ME

My name is Itumetse Seema. I have a Vodacom contract that gives me 4gig data monthly and when it's depleted I can top up. The problem here is that I cannot top up, when I do the data and airtime on my router disappears immediately. It doesn't matter how much I use to recharge, everything just disappears. I have asked Vodacom to check, shutdown and block all subscriptions but that doesn't help. I have called customer care for help but they have no clue what's happening. All they did was refund the airtime/data that I lost without even finding the problem and that refund also disappeared. Went to the Vodacom shop at Mimosa mall Bloemfontein but that didn't help because they are also clueless. I'm at a point where I'm really frustrated because I need my router working, hell I'm still paying for something that is giving me such a headache.