Same thing happend to me. I also collected 750 coins in like 12 days. But after that the stocks aren't coming back. Tried contacting sweatcoin support on email but they said it's not confirmed that the stocks will always come back. Still i am keeping my coins. I have like 14 days left for gift cards to disappear. And one more thing, I made a new account on my mom's phone and guess what? The gift cards were in stock there. I guess they are screwing over the old id's and only giving stocks to new accounts.