I guess it will become more clear through the complaint.
However, if you travel a lot, you may avoid similar issues when you openly inform the casino support or chat operator immediately after the registration. Imagine if you don't. The account verification, which the casino typically only initiates in response to a withdrawal attempt, uncovers numerous access points, which raises suspicion.
No one in the casino simply knows how often and where you travel, do they? No, unless you tell them.
Also, the deposit process does not require any verification procedures, so many players tend to conclude that it is hassle-free and take it as confirmation that everything is just fine. Well, it is not a guarantee.
Only after your account is fully checked, your gaming history investigated, and so on, are you entitled to withdraw.
You may quite easily find your account blocked due to further investigation.
I bet it is better to avoid that. Just a thought, of course.
Good luck with the complaint, of course.