my microsoft account has been blocked due to ISP which is AOL

So you're saying that you have AOL Internet service, and that you've been blocked from accessing Xbox because of that correct?

Quick update. I discovered the email tied to the account thanks to Microsoft Support. However, it's an AOL account I haven't used in many years, and AOL permanently deletes unused accounts after a certain amount of time. I contacted AOL to reinstate the account, to which they said there's just no way they can do it. Wonderful. Still have the cell phone number linked to the account, but apparently, I cannot use it to recover my account, per Microsoft Support. So now I'm trying to sift through generic AOL support responses given by their agents to reactivate the account, as the Microsoft Agent assured me the AOL account is absolutely still available since if it was permanently disabled, my Xbox account would have gone with it.

Yes for some strange reason, it has saved the aol account on my xbox so all i need is the password to get it to work.

But the AOL email is from an old version which is no longer used. Therefore i cannot make another one. ive emailed AOL to ask if they can reenable the account but they cannot. Ive tried the password reset thing but they said i didn't give enough information
for it to work.

Microsoft Rewards has been blocked for my account.

Hey WhyGen, have you inquired with the ISP about the issue, as Shad0wmanUK hinted at? If the users you cannot connect with are in fact only on TalkTalk or AOL (which Shad0wman mentioned are now one and the same), then I suggest giving your ISP a ring.