Hi Lisa Ann
Thanks for your comments.
I would argue against explicitly encouraging customers to share any deal done with them. They will do it if they want, but they should not feel like they are under pressure or being used, especially when they've had a bad experience.
A more subtle approach would be for the company itself to say online that you had both spoken and hoped a satisfactory conclusion had been reached, which may prompt the customer to confirm it publicly.
Hope this helps.