Duplicate I-765 submitted and approved

[elsapis]

I sent the application to renew my work permit but the USPS lost the package, I prepared another package and sent it again, this time it was received and processed... after a month and a half USCIS received the first package that was lost and also processed it with a different confirmation number, it has been impossible to communicate with anyone at USCIS on the portal or by phone, impossible, there is no information about it anywhere about what I can or should do, yesterday I received the card from the first application they had received And checking the status of the second request it appears that it was also approved yesterday but they have not yet sent me the card.

When I receive (and i will receive) the second work permit card, what should I do?, Should I return it? (where?), Can I keep both?, Will it cause problems later?

Thanks.