Router issue

I have a MTN made for me home contract with MTN. I get 15GB of anytime data and 15GB nightowl data. I recharge my router with an additional 30GB of data each end of the month, but that 30GB doesn't work immediately. Then for some unknown reason, none of the MTN workers at the MTN store I got the contract from, can explain to me what is going on. They say I must remove the sim and then restart the router, but when I dial 1555 the people there say that the sim must never be removed and restarting the router can't solve this problem. I have struggling for 4 months with this problem, no one can assist me. The people at the MTN at Matlosanna, next to the Ster Kennikor, can't nor want to help me. They never call back and are very rude over the phone. The "manager" at that Store is Louise. According to her, even is you call the area manager they will still ask her for help. Her is the reference number I got today- ********** 7595

Kind Regards. Tiaan Contact number- ********** 144 Router number- ********** 120