Complex sentence: On Christmas day Agnes receives a letter in the mail saying she can collect the money from the hotel her husband used to work at, so she holds Mr Billy off and sends her children to the hotel where they meet Tom Jones and tell him their story.
Split into simpler sentences: On Christmas day, Agnes receives a letter stating she can collect the money from the hotel where her husband used to work. She holds Mr. Billy off and sends her children to the hotel where they meet Tom Jones and tell him their story.