Question about Outlook Express

I converted to outlook.com many months ago.  I used to have problems with some senders receiving bounce messages on emails with attachments.  Over time that problem seemed to go away.  However, for the last week none of the Microsoft mail accounts for my family have been receiving new emails.  We have tested from several other domains, accounts, and systems, but to no avail.  Do you know if there is a quota that we may have exceeded?  We are using our Microsoft account email addresses having the @weldele.org domain as our outlook.com account emails.  It has seemed to work just fine until about a week ago.  Please help!  I have already checked filtering, blocked senders, etc.  and everything is empty or unchanged.