My sincerest apologies!

I'm so sorry for missing your calls and not being able to take care of you
since March 15th. I had a really bad UTI that knocked me out for a while.

I'm back now and feeling much better, and I'd love the chance to make it
up to you right away. You mean a lot to me as a customer — please let me
take great care of you again.

Thank you for understanding!