You can read more about this recall and the reasons behind it on the U.S Consumer Product Safety Commission page HERE and follow their links to claim your repair kit/harness or call direct for further advice on: 866-898-4999.
We had a Bumbo when my daughter was young enough to sit in one and always used it correctly. You should NEVER place your child, in a Bumbo, on a raised surface, they are supposed to sit in them, on the floor and you should NEVER leave your child unattended!! There are clear warnings and instructions for using the seats and I am not entirely sure that fault lies with the company here, but kudos to them for making changes to their product and taking the step to recall.
***Disclaimer: I am in no way associated with Bumbo seats or the CPC, I am just passing on some national recall information in order to inform and educate mothers and fathers out there who may have one of the seats and wish to return/fix them. All opinions in this post are my own.