Yes, it is not believable. If they put in place a new system, and in a week or two of testing or roll-out it was found to be missing captures, that would be understandable. But it went on for 5 months, and they didn’t know it was missing doing its backup job all that time? Nope. You are too incompetent to hold your jobs if your story is true.
Excellent point, except I refuse to give them the incompetency excuse. Continuous, long term incompetency that results in the erasure of a very specific vital piece of evidence is intentional.