If you just signed up for Public Mobile, it takes up to 72 hours for you to get the $10 discount. If you applied a friends code, ask if they got the CHICK CHING text message yet. If it's been less than 72 hours, they may not have got it. If it's past 72 hours, then you can reach out to a CS Agent with the links provided below.
It usually takes 3 days. if it's now beyond that, message a CS Agent at the the link below.
Keep checking your Community inbox envelope icon on top right after the ticket is submitted. CS Agent will reply to you there.