My account is over quota. Why it won't let me upgrade?

please help us we are unable to upgrade via the portal. we are over quota

I have checked your account and I could see you were over-quota; however, when I was checking your account I would see you were able to upgrade successfully and your account is now on gold monthly subscription. 

So your account is not over-quota anymore, you can also check this and your invoices by following this guide: How-to-Check-Invoices. 

Please do let us know if you have questions, we will be glad to help you.