Is DUMBLL a scam, or is it legit?

Since November 2021 I was operating with this broker. The first 2 withdrawals of 100 usdt were correct. On March 8, 2022 I tried another withdrawal of 7000 usd but it was rejected without reason. The next day I tried another amount (70,000 usdt) and it is still in process. April 4 with only 100 usd is still in process. I wrote to them and they told me that I had to pay some taxes that are not listed anywhere and it smells like a scam, especially with the end of the answer (have a happy life). I want to withdraw as much as possible or at least my deposit of 13700 usdt

Dumbll is not suppose to trade in securities. The regulator ORC in Canada/ Ontairo says Dumbll is not operating legally. Dumbll Limited is therefore not authorized to collect tax to release my investment of $29271.00I am unable to withdraw the balance of my initial deposit. $29271-$7000 = $22,271.00 $22,271.00 Balance. Dumbll know its not authorized to collect taxes, as it is not operating legally in Ontario / Canada to accept funds.

It required 20% tax and then blocked my account.

The customer service never replied me.