Citibank

I had a checking account with Citibank . I closed the account because of their bad services. I wanted to get cash but Citibank refuses to provide me cash. They stated that because I'm no longer their client they don't cash the check, which was issued by them.

What kind service is this?
I would understand if I don't have an account with them and want to cash a check issued by another bank. However, this is not the case. I had an account with them. They have my money and now refuses to provide cash to me when I closed the account.