Hi Brizman.
Similar happened to me. I self excluded from Gday Casino ages ago (Caddell Group). I opened a 21casino account and played for about a year. I then went on chat for a query and all of a sudden my account was closed, citing i was self excluded.
I emailed them asking why this happened. They said it was because I had used a different name (Shortened Version), and different email. I countered with the fact of my Id was the same for verification both times ( Driving Licence with unique number) and asked for a refund of net deposits.
They refused saying i tried to decieve them using a different name again. This time I said i was prepared to go to the UKGC with my findings and show the interactions I have had with 21casino.
The following reply was an apology and asking for details of my bank to process a refund. If you are down in Redbet, I would push for the similar net deposit refund, if you used same Id for verification, use this as further evidence as to why you should have been excluded on the merger date.
Good Luck
Delboy