no assistance for a simple request

I have been trying for 3 days to switch a debit order from my husband's account to my bank account. We have completed all the necessary forms as well as a letter requesting the change. But we have made no progress and upon contacting the call centre this morning and attempting the email the documents 3 times the call centre agent has informed me that the attachment is too big for her to download and she cannot affect any changes. Also the admin department whom we initially contacted cannot be contacted telephonically. I find this unacceptable. I am now going to fax through the exact same documents requesting the change to be made and will see what happens now.