Mac Mail AOL/Verizon mess cannot retrieve my email

I just got a new Mac Mini. I turned it on and now my Verizon email account on all my computers is working as if it is under water. I have a Verizon address and they were migrated 2 years ago to AOL. It has been working just fine and something happened today when I plugged in the Mac Mini. I have been going round and round - AOL wanted to charge me for a Pro account, Apple says it cannot help because it is the Verizon server, Verizon says they no longer deal with the AOL accounts ... Everyone is baling. First off, there are conflicting tales on line as to whether I should be using POP or IMAP. I believe I have been using Pop. Btw, my iPhone is messed up as well. ANy ideas on how to straighten this all out?