Your plan and billing information are managed externally

I have cancelled my monthly subscription through Google Play (which I have had for years) in order to sign up for a yearly subscription through Dropbox.com. Dropbox now asks me to upgrade (since my Google Play subscription has ended) and when I try to do that, I only get an error message ("Your plan and billing information are managed externally."). There is nothing else I can do. I removed the Google Play subscription completely and tried logging in via a different browser/incognito mode (as one solution on here suggests). So far, nothing has worked. What is particularly frustrating is that I cannot contact Dropbox support because I am on a basic plan now. I have been a paying customer for years and I intend to remain one, but I cannot seem to get any help with this from Dropbox directly.

I somehow have more files than the space that i have. My files cannot therefore synchronize and i can't uppload any other files. I tried to buy more space, but i get the message  that" payment should be handled externally" not from inside the account. I tried with apple pay, but i stil get the same message in my account. Apple account is charged but i see no upgrade

I am unable to upgrade my account. Every time i try it says "account is managed externally" and i keep going around in circles. I currently dont have enough space for my content and work. I also tried to contact dropbox and only managed to get through to support once - and they were unable to solve it. Help!

Hello,

I am unable to upgrade my plan using the Dropbox.com website.  My subscription with the Apple App Store has already expired, and I do not want to upgrade through Apple.  I keep getting this error message:  "Your plan and billing information are managed externally."  How can I upgrade without using the Apple App Store?