I didn't participate in any gambling or do business with somebody whose business includes gambling to my knowledge. I barely used the account at all after initially setting it up when building something for a client (an entirely non-shady company that you've probably heard of) that used their API.
They said this:
Unfortunately a manual review has determined that you are ineligible to use the Coinbase platform to purchase Bitcoin. We’re sorry for any inconvenience that this may cause.
And when asked why, they said this:
Sadly, I don’t have any information before me to answer as to why such a decision was taken, but this decision is final.
The only thing I can think of that I did that might have been suspicious was to access the service from outside the US and switch Authy to a non-US phone number after previously using a US phone number.
They said this:
Unfortunately a manual review has determined that you are ineligible to use the Coinbase platform to purchase Bitcoin. We’re sorry for any inconvenience that this may cause.
And when asked why, they said this:
Sadly, I don’t have any information before me to answer as to why such a decision was taken, but this decision is final.
The only thing I can think of that I did that might have been suspicious was to access the service from outside the US and switch Authy to a non-US phone number after previously using a US phone number.