Sim card has no signal

I ordered a Sim card and paid R479 for it. RAM delivered the sim card and few hours after that I got an sms and email saying that it is active but when I put it in my phone it has no signal or network, I tried putting it in a router it still won't work. I sent messages and they are not responding and I can't get hold of them using their contacts. I bought the sim because I wanted to work from home but this is very inconveniencing and very bad service.