I agree with BrewBama and also switched to using dry yeasts almost exclusively for the same reason. You can harvest/save slurry from the fermenter when dry yeasts were pitched too. It makes no difference whether the origin was liquid or dry.
As for your current problem. Even though Kveik yeasts can be fermented at higher temperatures, they can still be compromised or killed if they get too hot. Airlock activity isn't a good indicator of fermentation. If you're fermenting in a bucket, be aware that the lids don't always seal well and you may not get any any bubbling even if the beer is fermenting. If you are using a bucket, wait until the new yeast arrives and then open the lid just enough to see if there's any Krausen (foam) on top or scum around the sides of the bucket just above the liquid level. Either will tell you that the beer is fermented or has finished actively fermenting. If you see neither, pitch the replacement yeast. Hopefully, you ordered ice packs with it and it's not hot when you receive it.
If you see foam or scum, check the gravity to see if it's close to expectations. If it is, wait at least 48 hours and check again. If it remains the same, fermentation is complete. Gove it another week and then proceed to packaging your beer.