To whom it may concern,
My account changed from PLUS to PREMIUM this month.
When I tried to upgrade my membership level last month, the system did not work properly, so I contacted Mark and the upgrade was completed.
I could not enter the code UPSAV2500, because the system responded with an error code when I tried to upgrade my membership level.
I wonder if I am entitled to get 500 points.
Regards,
Yutaka
(ymoteki)
Hi Yutaka,
If you downgrade to Plus and then upgrade to Premium and enter the referral code, you should be given those points. If you have problems, please let me know.
P.S. Don’t worry. You will not be charged again when you do all of this! 
The system knows that you have already paid for this month.
I could not downgrade my account; the system responded with “500-Server error”.
Yutaka
Hi Yutaka,
Sorry about that but now it looks like we have identified and fixed the issue you were having. Our payment system was having trouble dealing with some Japanese characters in your payment information. This is the same issue you had when initially trying to upgrade. It should be fixed now so please try to downgrade/upgrade with the coupon again. Sorry for the inconvenience.
I don’t think the issue has been fixed.
The same response from the server, after clicking the button described as follows:
Yutaka
Additional information:
When I purchased extra points, there was no problem.
Anyway, I think that security should have priority over any other functionalities and bonuses.
Yutaka
Hi Yutaka,
It should be fixed now. We are pretty sure we have it licked this time! Please try again.
Hi Mark,
I was able to downgrade to Plus and then upgrade to Premium.
I appreciate your hard work.
Yutaka
Great!!! Thanks for your patience. Actually, your help allowed us to find and fix this problem that has been a problem for a while.