Sophia: Did you buy a top-up voucher at a store, or did you use a credit card? In either case this just adds credit to your prepaid account. You can then log in to self serve to apply that credit to a booster.
You still need to activate the booster, Sophia. When you add funds, the account doesn't know yet what you want to use it for.
So you need to click "Add booster/addon" from the login page, then select the Talk booster 500, click "Add to my order", then underneath whatever it says (mine says "top up to purchase booster" but yours should probably say something like "add booster". Then you can call :)