Company #2 can keep receiving the spreadsheets and do whatever else they want with them. They just wouldn't be used to do the work you've described. With your basic description it seems like it would be pretty straight forward to do with PHP and MySQL using a single table.

The emailing and attachments can also be handled with PHP, though I'd suggest using PEAR to allow SMTP mailing instead of PHP's normal "mail()" function.

You can explain this to company 2 as the difference between a clean and manageable solution costing X dollars or a convoluted solution that will cost 2 to 3 times as much. That should help them make the right decision.