How can i get Blackberry Mail booster on T-Mobile PAYG?

[nikkimariam]

I've had a blackberry for about 3 months now and i haven't been able to use the full functions such as BBM and BB mail. I was on the T-Mobile site a few days ago and it said something about the BB Mail booster. I have tried to do it but the site is not helpful enough with instructions. Can anyone help me get the BB Mail booster on PAY AS YOU GO!?