Bad service and Rude consultants

I have received a call from cellc collection department, the consultant I have spoken to was extremely rude regarding a debit that has bounced due to a change in banking details and when advised that I will be taking up her rude behavior I was asked to please do so. Further to this I spoke to a consultant a few days earlier who has advised my banking details will be updated. I will not be using this provider once my contract term is complete.