Docs to Go has failed

That was until recently when synchronicity was lost and a website suggested possible fix was to wipe the phone files and re-pair which hasn't proved possible so I now have no files on the phone. Strangely the iPad still works.
When I went to the App Store to see if others were reporting the same issue I found that reviews are old. I notice that Docs to Go have introduced two versions where only the Premium edition allows Wi-Fi support and the Standard edition is free. The App Store shows "Open" for the Standard and a fee for the Premium which I take to mean that I have been downgraded to Standard even though I paid a fee when I originally acquired it.
Assuming that Docs to Go is now defunct I am looking for an alternative. I don't like to use iCloud as I like to keep my files off other peoples' servers and I don't like sending files back and forth to the cloud as some are sensitive like my password store.
Have other members a possible solution?