Everyone here at R2R knows that TBS is a great vendor to work with. Sounds like this is a carrier issue, so I don't take this like you're speaking badly about TBS.
With that in mind, I'm willing to bet this is not their first order that's been delayed by shipping. Maybe
@LiverockRocks will be able to pop in here and offer some suggestions on how to best handle this.
I lieu of that, I don't think there's much you can do other than hope for the best. I'm not trying to be gross, but when you get your shipment I'd give the bag the sniff test. If it still smells fresh like a beach, you're in good shape. If it smells horrendous, you know that you had a lot of die off.
Good luck with your shipment!