There are three reasons you might receive the "You've reached your usage limit" error:
If you're using a free trial account, remember that the tokens granted in this trial expire three months after account creation. To continue using the API after that point, you'll need to enter billing information and upgrade to a paid plan.
Another potential explanation is that you may have created multiple accounts using a single phone number. We only grant free tokens to the first account created with a given phone number. In this situation, the solution is to log into the account you originally created to access those initial free tokens.
If you're already on a paid plan, you may need to either increase your monthly usage hard limit. To set your limit over the approved usage limit (normally, $120.00/month) please submit a quota increase request.
Why did I get charged if I'm supposed to have free credits?
Only the first API account verified with a given phone number is granted free trial tokens. A phone number can be used up to 2 times to verify sign ups. We only provide the free trial tokens to the first sign up, not more.