Option to increase quota does not exist... or am I mistaken?

Upon searching for "quota" in the support forums I only see the following three results:

https://share.riseup.net/#5HbPszp1surG8GoIwjwdag

And upon clicking on the first link it opens the following page:

https://support.riseup.net/en/knowledgebase/1/docs/3-how-do-i-increase-my-quota

where #3 says "Increase your quota. The default can be increased by visiting https://account.riseup.net."

but I can't find anywhere in the account back-end where this option is...

Can anyone else please guide me in the right directions?

Thanks in advance!