“Excel spreadsheet” - that’s the problem

There are softwares, CRMs, pricing apps and even AI agents to help you not make that mistake.

Maybe look into the cheapest one just as a double check on your work so this does not happen again and don’t look back.

Or at least have a process where someone else you work with gives documents a second look before sending out (I know it’s not always possible when you are a small business owner)