Sorry to hear about this, but things don't magically "hop off" David. Possible installation error there? When you say U-bolt, do you mean the u-bolt that holds the spring pack to the axle?? It doesn't mount there, it mounts forward of the u-bolt, towards the cab. I looked at
your pics and it looks like it is in front of the u-bolt but it's hard to tell...
Jonathan Hanson warned me that his had once "walked off" the spring perch, so I watch that rather closely but so far no problems on trails in Moab, Colorado and Montana.
And BOOM! what...? The bag popped? Overinflated maybe? I run 65 PSI in town and 85 PSI on the trail when loaded with camping gear. With a Shell model you shouldn't be nearly as heavy as me, so 60-70 PSI should be plenty on the trail, maybe 50 PSI-ish in town.
I don't think you'll have better experience with Firestone airbags as they are virtually the same product as Airlift. If the installation and inflation are correct for your application but just not working, the Deavers are a great option. I was amazed at the travel Ursidae69 has with his Deavers.
I prefer the ability to adjust the airbags over the fixed spring packs but that's because I don't plan on keeping the camper on the truck year round. You can order Deavers with 1.5 - 2 inches of lift and throw some coil spacers up front for an equal lift all the way around.
I would start with the Deavers first if you go that route. With the camper on the back, the Deavers will bring your back end up to level so your headlights are not pointing to the moon.
Sorry to hear about the problems already but it doesn't sound like the bags were installed and/or inflated properly. Have anymore info you can share?