Do I need to subscribe to 365 in order to access MS Exchange for my emails to and from Outlook Classic

A week or so ago, I became aware I could no longer Reply, or Forward emails I received, using Outlook Classic and MS Exchange, with a personal account. I have been paying $4.00/month, for years, for MS Exchange. When I finally got through to MS Help, they told me that I needed to subscribe to 365 at another $10.00/month. At all times I had 2024 Office Professional installed on my PC; used Outlook Classic and paid for MS Exchange. I have a Trial Subscription to 365. Can I let it expire and resume my previous usage without interruption? OR, I transferred my domain/email address to MS Exchange from GoDaddy. Would it be easier to reverse the process?