What is a good answer to tactfully let a customer know that a co-worker was downsized...?

Question

...so it doesn't sound like they were fired for doing something wrong, but they're definitely not with the company anymore.

My concern is when they call the office and she's subsequently not available for phone calls.

Answer 1

Don't say she was downsized or give any details, just say she is no longer with the company. That doesn't imply she got fired for doing something wrong - she could have just left on her own for another job.