If you're using iOS and having trouble purchasing Jelly, you may have disabled in-app purchase.
Go to Settings > General > Restrictions > Turn on In-App Purchases.
If you're using recent iOS versions, please follow the steps below to check and enable in-app purchase:
Go to Settings > Go to Screen Time and turn it on > Go to Content & Privacy Restrictions and turn it on > iTunes & App Store Purchases > In-app Purchases > Check Allow.
If you still experience difficulties after trying the steps above, please contact Customer Support on Weverse.