Did you have two day delivery? Were they actually warm to the touch? This happened to me once from Iherb, I used them anyway... not sure if they worked or not. In the future try ordering from here:
http://www.ocproactivehealth.com/natren.htm
 
They are cheaper and they had what I needed in stock. I will use them from now on.

By the way, how are you doing? How are your arms? Hope the tingling and numbness have gone away.

This happened to me on 2 occasions - Iherb actually shipped the probios without icepacks.  I called them, they gave me a refund both times.  I don't order from them any more because it's such a gamble as to how they send them.  I didn't use them after they were out that long.  Maybe call Natren and ask if they're OK for 48 hours unrefridgerated? 

I live in BC Canada and tried a new source, Nutraways, for Natren. I had same experience. I took a day's dose and started a whole new set of reactions. That's one way to test for potency but don't recommend. They sent a new order on ice with same result (melted and warm) so gave that up... I suspect they didn't take care with refrigerating before sending also.
I spend time in USA and IHerb worked fine, but have to say the Natren site itself was wonderful service on the phone and cold delivery...a bit more $ but worth it...
I buy here in Canada, through a healthfood store now and so far so good. I would order from Natren site if in the USA but have not tried all the others suggestions.
Has anyone had success with testing the products as suggested..(immersing in water for a time?
 

Order from Natren and get the discount for ordering monthly (Actually they just call you monthly to see what/if you need anything. You don't have to order every month).

This has happened to me and I was told that they should be okay. You can leave those probiotics out at  room temperature for 3 weeks and they are still potent. I think it depends on how long they were exposed to heat. they might lose a bit of potency. How long were they hot? You got to think on those shipping routes and planes it's pretty cold up in the air.  I would ask for a refund and have them shipped them one day delivery. I have started to get a local health food store to order them for me so I don't have to keep paying for shipping and this way I know its cold. 

This has happened to me with Iherb but they will gladly re-ship. Actually this happened because I chose the 1-3 day shipping option, rather than the expedited overnight option. Whenever I choose expedited overnight (for 12 dollars) it comes cold.
 
If you are worried I would use Natren but they do take a long time to process and ship IMO.

Hi ,! When I first got my probiotics from dr's office from LA it stayed all day long in my car and it was summer, and when I reach Las Vegas I totally forget to take them out of my car that night and  I was in confussion that they might have gone bad ... So I tried to make yogurt  using 1 capsule of mega and guess wt I got yogurt after 10 hrs of incubating so I got relaxed that they were still good ..... I DOnt know I never tried again but we should try to see if it works because yogurt is made by active cultures of probiotics....