Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
You are in the position of a person who has burned up a $100 bill. The bank will not give you a replacement unless you can prove you really had a bill that burned up: provide them with the ashes.
You have lost track of the Product Key, so unless you have adequate alternate proof of the purchase, MS will not replace the product key.
Here are MS's replacement policy. I strongly suspect you don't have enough proof to satisfy them. But maybe you will get lucky.
Replacements
How to obtain a new product key for a Microsoft Office suite, Lost Product Key support - http://support.microsoft.com/kb/823570
If your purchase was through the Microsoft Store, You can contact them at 1-877-696-7786 or login using your credentials in the link below: http://store.microsoft.com and they may be able to provide download details.
If your purchase was through Digital River, refer the following link: https://store.digitalriver.com/DRHM/servlet/ControllerServlet?Action=DisplayContactFormPage&SiteID=msshus&Locale=en_US&Env=BASE
Get replacement product key from Microsoft - http://office-watch.com/t/n.aspx?articleid=1628&zoneid=12****
How to identify, locate, and replace a product key - http://support.microsoft.com/kb/811224
Replace lost Office product keys 2003, 2002, 2000 http://office.microsoft.com/en-us/help/replace-lost-office-product-keys-HA001150834.aspx****
Replace a lost or damaged Microsoft Office 2007 or 2003 product key -http://support.microsoft.com/kb/2548260 How to replace a damaged, invalid or lost product key for a full version
If you have followed the tips in the previous section and you still cannot unlock Office with your product key, or if you cannot find your product key, you can obtain a new one. To do this, contact Microsoft Support. Find the support telephone number for your area by running the Product Activation Wizard on your computer. For more information about how to run the Product Activation Wizard, click the following article number to view the article in the Microsoft Knowledge Base: How to contact a Microsoft Product Activation Center
When you contact Microsoft for a new Office product key, please have the following items available for the customer service representative:
· The product CD-ROM.
· The computer serial number on which you want to install the Office suite.
· The readable parts of your original product key (if available).
How to replace Microsoft software or hardware, order service packs, and replace product manualshttp://support.microsoft.com/kb/326246/****