iMessage size does not reflect reality.

I purchased a new phone in Feb. I did not restore a backup. Messages was taking 3.6G of my iDrive. I deleted all but 5 messages.

I now have 4.7G of iMessages with only 30 messages. It never reduced in size. How do I get iCloud to either mirror these messages so I can delete them, or get iMessage to reflect my phone? Off/On in the settings has been tried with various reboots, etc. This seems to be a fault in iCloud.

Can I just delete EVERYTHING in iCloud and start over?