Without know what support said all any of us can do is guess.
Proton
Empowering you to choose a better internet where privacy is the default. Protect yourself online with Proton Mail, Proton VPN, Proton Calendar, Proton Drive. Proton Pass and SimpleLogin.
Proton Mail is the world's largest secure email provider. Swiss, end-to-end encrypted, private, and free.
Proton VPN is the world’s only open-source, publicly audited, unlimited and free VPN. Swiss-based, no-ads, and no-logs.
Proton Calendar is the world's first end-to-end encrypted calendar that allows you to keep your life private.
Proton Drive is a free end-to-end encrypted cloud storage that allows you to securely backup and share your files. It's open source, publicly audited, and Swiss-based.
Proton Pass Proton Pass is a free and open-source password manager which brings a higher level of security with rigorous end-to-end encryption of all data (including usernames, URLs, notes, and more) and email alias support.
SimpleLogin lets you send and receive emails anonymously via easily-generated unique email aliases.
Unfortunately, our anti-abuse algorithm detected matching accounts that correlated with your own, and in order to protect our interests, we will be unable to assist you in reinstating your account.
What exactly did support say?
I replied on another post.
....did you make it on your work computer using your ONLY email address? And now you're trying to make ANOTHER account with the SAME email address?
Sorry, but the way you emphasize "work computer" like that makes it the unique identifier leads me to believe you misunderstand how things work.
I don't remember what email I used for the back up on the work computer. I'll check. If it was the same I guess that's the issue. If it was not the same is this ip based?
Your region? Is the service you are trying to acquire available to Canadian customers?
Not OP, but as a Canadian I have all Proton services, so that is a non-issue
Multiple free accounts are agains their terms of Service. One free account and multiple paid accounts. That could help.