Error opening document [content.xml at 2,76869(row,col)]

I get the following error message when opening a spreadsheet:
Read Error.
Format error discovered in the file in sub-document content.xml at 2,76869(row,col).

How can I retrieve the document?

Can you please upload your file hier. Thanks.

Leisure World Expenses.ods (20.3 KB)

Leisure World Expenses.ods (20.5 KB)

Can you tell what exactly did you change in the file, that would cause the problem?

I have no idea what caused this! I was merely tracking expenses associated with a move. Went to open the file to make an entry and received that error message.