Hi, great news! my asset pack gets accepted by GDM and now it's LIVE!.
You can purchase it through this link: https://www.gamedevmarket.net/asset/complete-gui-essential-pack/
Please let me know if you are able to choose a different payment method other than Paypal and succeed in it, I think GDM accepts credit/debit cards as well.
Noted that, the pack costs $5 due to a 30% commission fee for GDM.