CANCEL THE DEBIT ORDER PLEASE!!!

Had a ridiculous billing on a router I only used for 3 days, laid a complaint here and a cell c rep called. I thought this matter was resolved because she said she had listened to my phone convo with the lady who sold me the router, and confirmed that I was not given the correct info. She said that I wouldn't be paying a single cent, and the router was collected. Today a debit order bounced on my account because I did not have sufficient funds - thankfully. Please cancel this debit order on my account I don't want to incur unnecessary bank charges. I'm on my last nerve really!