Hello - did they put just an ACH block only on your old account? Because unless the account is either closed altogether or on credit only status, these companies are able to find other ways to deduct the money from your account other than ACH withdrawals. Also, even if you have emptied your account of money to keep them from getting at it, they could instead take your account into the negative, and then you would owe money to your bank.
Just to be safe, I would double-check with your bank and make sure that if your old account is to remain open, make sure it is made to be CREDIT ONLY, so that absolutely no kind of withdrawals by either electronic or paper check means can be made.