I have the exact same problem, have you found a solution yet?
I am trying to rent a server for conan exiles on the PS4. I charged the exact amount of euros needed for a 20 slots PS4 server for a 1 year rent. Even when I log in to the G-portal website I see the right amount in my balance information. However when I try to activate my server I still says that I don't have enough credit. I double checked the amount of money and it is the correct amount so I don't understand why I can't activate my server??