unauthorized debit order??

Debit order that has gone off this morning after I have not signed any paperwork or contract, and cancelled over the phone a few days after starting the telephonic application last week, because I cannot afford it as of this moment, but rather in the near future possibly because I am still a student. Now I have to wait and see the extra bank costs of reversing the debit order, and hoping that someone responds to my e-mail so that the debit orders can be stopped.