Pay for No Service

i bought 2 tablets for my kids for Christmas i Received it in November till now they cant use it because they don't activate the Internet on the sim cards i have been phoning going from shop to shop still cant get it fixed if you call you get people like Sharmain from Trade partner that don't want to help is rude and i don't know how they employ people that cant do they work solve a problem or work with customers i have paid every month but No service so i would like to know they don't get data every month that i am paying for no one helps to fix the problems so i want a refund on all the months i cant use these Tablets they are so vast taking your money but when it comes to service and fix what needs fixing they just cant help so what to do pay and pay for things you cant use then i can just as well go and throw the money in the toilet and flush it away because that is whats happening now they keep on taking my money and i don't get what i pay for