My wife and recently got the game and love it.

However each of our phones won't allow us to connect to the in game store.

We have Android HTC Sense pre Google Play. We have "Market" app instead and cant seem to find anywhere to change the "Buy in App" others suggested.

Can anyone help?

Same problem here. (Huawei mediapad x2 Android 6.0)

Relevant section of response I got from FFG software:

We are aware of some issues with the Elder Sign: Omens store. We are currently in the process of updating this app to 64 bit, and the store fixes are being rolled into this update. I do not currently have an estimated release date, however it is planned to finish before the iOS 11 update.

So, no immediate fix or workaround, but they know about it and are working on it.