Proper database backup

I've been using Constant Contact for over three years from my web host .  The Constant Contact service was very important in keeping our club members together and interested in our activities during Covid.

Recently discontinued your service leaving me unable to access my data.  

I opened a new account with Constant Contact and all has gone well except for re-entering my data from my old account.  

I had an old csv file but it was not a proper database backup.

The comma delimited file was a flat representation of the data with no schema.  Restoring it was difficult and time

consuming.  For instance the many tags I had characterizing each club member were corrupted.  Therefore, all the tags for

each member were checked.  I had to access each one and uncheck the incorrect tags. 

There should be a way to save your database and schema so it can be restored.  If there is a more correct backup method, I missing it and would like to be directed to a better procedure than the one I used. 

Thank you for comments and any help you can provide. 

Regards,