to me it sounds exactly like a scam, by paying out with BTC from new deposits -- especially as I'm not the only one who had his account with a 2 figure BTC amount simply deleted.
I created a nic on this forum just to post that I have had my account deleted as well. I had 2FA set up and all was working well for about 3 weeks and now I simply don't exist anymore. Even when I click "forgot my password" and enter the email I registered with, I get the message "Sorry we could not find this email in our database". I have submitted tickets a week ago and no answer. It is 100% not user error. Whether scam or negligence, btc-arbs.com has robbed me of just over 1btc by simply deleting my account.
Get your money out ASAP (if you can) is my advice.