Sending, receiving, and organizing email in Outlook.com
@f will said
They are stating my email address is locked, but I am receiving all other emails just fine ... The agent said to contact my email provider to get a new email address, which doesn't make sense to me
Almost all high volume mailers use a third party mailing service (ESP) and there are any number of things (not your fault) that will get you on their blocked list. This means the emails were probably never sent. This can happens when a single temporary glitch (like a full mailbox or a temporary server timeout) causes an email sent to you to "bounce". To protect their sender reputation, the ESP marks your address as invalid and blocks future delivery.
They should have a process in place to get your email off of their blocked list. But it sounds like you have already been down that road and they are not going to help.
All I can suggest is that you create a new outlook.com alias (a different email address but delivers to your existing account) and give them that one.
https://support.microsoft.com/en-us/accounts-billing/manage/how-to-add-an-email-address-or-phone-number-to-your-microsoft-account