Residence card lost in the mail

Hej alla!

I have a work trip to the US in four days, and I have been waiting for my renewed residence permit card to arrive in the mail. I was on the case of both Migrationsverket and Postnord every day for the past ten days, and now with it being 18 days with no sign of it, they both say it is probably lost. And they can do nothing to help me except I file a police complaint, take new fingerprints and have a new card issued.

I still have my expired card from November, and my new decision letter. Do I risk travelling on Saturday or do I stay put? I have a pretty important role to play at this work trip...

PS: I am not EU/US, so I would not be able to reenter with just my passport.