Recommenders have submitted reference letters but I missed to submit my application

I feel guilty and not sure of if I should inform my recommenders of this issue.

A school I intended to apply has received the reference letters from all my recommenders, but as the deadline was approaching I just found that I could not prepare something required by the school in time! So, considering the amount of application fee, I decided to close my application.

Now I feel maybe I should have told my recommenders about this issue, yet, whenever I was about to write a sorry email then I withdrew my draft.

In such a situation, am I suggested to say sorry to my recommenders formally?