Did you delete the first smart campaign? When you say the data in the smart list was lost, do you mean the filters and triggers were cleared out?
If you clone a smart campaign it will not bring in the same run history and members. You may have to build out the smart list and smart campaign again if you deleted it.
The smartlist ran and we put a constraint on the list and then the list went to zero individuals in the list.
Use a "member of smart campaign" filter, it will give youn the list of people who went through your smart campaign.