Lost all my eMClient (yahoo address) emails

I lost all my emails 3 days ago (29/11/2022) from my eMClient yahoo account. My old address was gerskin2000@yahoo.co.uk which worked well in eMClient but I mistakenly tried to upgrade the yahoo part of my address. This resulted in a new yahoo account gerskine72@yahoo.com. I expected all my emails to be transferred automatically with the new address, but this did not happen. They now all seem to be lost.
Tried contacting yahoo customer care who are impossible to contact by phone without subscribing to a paid customer care service. I don’t want to do this.
How do I get my emails back? Some of them are very important (and, yes, I know I should have backed them all up in case of problems - but I didn’t - so too late now.)
Can anyone in the forum help me? My existing eMClient is the free version so it is impossible to contact eMClient customer care without changing to the paid version. Where have I heard that before?
Please help if you can, I would be very grateful for any suggestions or advice.

I mistakenly tried to upgrade the yahoo part of my address. This resulted in a new yahoo account gerskine72@yahoo.com I expected all my emails to be transferred automatically with the new address, but this did not happen. They now all seem to be lost.

Normally you wouldn’t loose your emails via changing Yahoo email address’s as each address has a “separate cloud mailbox space” associated with it. Changing to a different Yahoo address would just give you a blank new mail space with your new email address.

The only way you would normally loose all your Yahoo account emails is if you selected to eg: Delete your old Yahoo mail box in whatever process you did which I presume you didn’t do.

So all you do from the sounds of things is “first go online via your browser” and go to the Yahoo webmail login and “see if you can still login with your original Yahoo email address name and password”. If it doesn’t login ok, then click the Yahoo forgot password webmail link there. You should then be able to reset your password and then login & see all your old mail.

However “if you still cannot login to webmail” even after trying to reset your original email address password online" then you will definitely need to contact Yahoo technical support.

However “if you can still login ok” to your original Yahoo mail box online via webmail, then go into eM Client and click “Menu / Accounts” and remove and re-add your Yahoo email account via the automatic email wizard at the top.

Note:- If you do remove and re-add your Yahoo account, backup eM Client first via "Menu / Backup incase of any problems. You can see when the backup is complete via “Menu / Operations”