I would be upset too, but there's really not much that will be worth your while, pursuing this account at a bank that clearly no longer wants you as a customer.
1. you got your $4k back, and they're giving your $50 back, wouldn't worry too much about that
2. your employer knows (or will know shortly) that they got your paycheck DD back, so you can follow up with them about getting it put into a different account
3. find a bank (or better, credit union) that has a competing APY, and wants you as a customer. depositaccounts.com is a good resource