Softbank Hodai won't connect to Sprint?

We switched to Softbank in order to use their America Hodai plan when we travel to the US. We're supposed to be able to use it wherever Sprint is available. The plan is great when it works, but it keeps disconnecting from Sprint, connecting to other US carriers, and won't reconnect to Sprint. Softbank's technical support won't acknowledge this happens, and insist there's a problem with our phone or sim, but we've gotten both new phone and sim (from them), and the problem continues. Strangely enough, it immediately connects to Sprint right after we call Softbank's technical support, but disconnects again a couple days later. Has anyone else experienced this, and if so have you found a way to resolve it?

Admittedly not much of an expert on mobile phones, but have you set your phone to connect to carriers automatically or manually? I would try manually.

I too recommend setting it to manual carrier selection instead of automatic. When in automatic, the phone constantly keeps on searching for the strongest signal and switching between different carriers.

Softbank's instructions are to keep it on automatic, but we try manual too, with the same result. It won't switch to Sprint, even though it's one of the visible options. Not usually a "conspiracy theorist" but in as much as whenever we call Softbank, it immediately switches to Sprint after the call, we can't help but wonder if Softbank isn't intentionally trying to limit the Hodai plan use.

This was a big reason why we stopped using the America houdai (and Softbank in general) and now just get SIM cards separately when we arrive in the US. It wasn't worth the stress of making sure that it was connecting to the Sprint network every time you used the phone, and manual or automatic never seemed to help either way with our phones (iphones, but this was at least 4-5 years ago). It was too stressful wondering if the phone would switch to a different carrier and incur large fees when in use, and since Softbank here in Japan is generally terrible anyway, we got rid of them and never looked back. We never found a solution, and found Softbank customer service completely clueless. T-Mobile has tourist sims for 3 weeks for a decent price, and you can buy even cheaper ones than that on amazon and have them sent to any US address. Glad we switched; Softbank was a nightmare for us in general anyways!

Thanks Murny. It's helpful to know someone else has experienced this. Today the Softbank help person insisted this never happens to anyone else, and that the problem must be in our phone. Sorry for your frustrations, though.