I have hundreds of emails I cannot delete online in my Yahoo Mail Plus Account?!?

[Mary]

Very frustrated! I am trying to clean up my inbox online and there are literally hundreds of e-mails I cannot delete - most of them are from 2011 and 2010. For example - when I run a search for "Facebook" and filter to the year 2011 - I have 1,230 messages. The odd thing is - it does not show the location of the e-mails (ie. Inbox, Spam, Sent etc) The location field is blank and when I try to delete or move them to another location, I receive an error message.
Also - I have somehow managed to change my default view from showing one page at a time worth of e-mail to having one continuous page of all my e-mails and I cannot figure out how to change that back.
Any help on these two issues would be greatly appreciated seeing as how it seems Yahoo does not have any tech support for the service I am paying for.