Something similar happened to me once but with credit card company and no they can not do a stop payment on pre-authorized debit, you have to get the other party to stop that. I was told that after you signed that agreement they have the right to withdraw money as long as you still hold that account even after their whatever service is no longer needed also trying to get these unauthorized payments would be pain in the a** so I always avoid going into pre-authorized debit agreement. I'll just write my checks or making payments through online banking, yes it is inconvenience but that convenience might come with a big price tag.
Oh I even had mortgage payments deducted from me after I paid off the mortgage and getting it back was a big headache! Just try not to sign these agreement if you don't have to that's my 2 cents! Hope everything works out for you at the end!