There is a class action lawsuit against audible for people that have lost credits due too the following:
1.Lost credit(s) due to rollover
2. Lost credit(s) due to cancellation of membership
3. Lost gift membership credit(s)
Anyone who has lost credits due to any of those reasons may be entitled to a free audiobook. More information here:
https://www.mckeesettlement.com/(Personally I got an email from audible because I am a subscriber not sure if anyone else did)