For the good of all:
This may not apply to all former RingPlus accounts, but it does apply to what were my former RingPlus "Mad Fiesta Free" and "Mad Plum" accounts.
Each of these accounts were transferred to Ting during this past week. My DIDs work fine there for in/out calls, etc. I'll use up the $35 credit and see how it goes.
But, the accounts also still live on in a goofy way at RingPlus. Each was converted at RingPlus to something called "FluidCall International," with an expiration span of 12 months. And, if you still have credit at RingPlus, it works as named.
I put the VoIP credentials of one of my accounts in the Zoiper app on my cell. Calls to domestic numbers do not work. But calls to a UK echo-text number (011 44 148 360 4781) worked fine. I was charged 3 cents for the fraction-of-a-minute call; that charge was deducted from the top-up credit still shown on that R+ account.
So: silver lining for those of you who had R+ accounts, with remaining credit, and place international calls: it looks like you can use-up your credit making international calls during the next 12 months.
Convenient for me: I'm off to Canada the week after next. Wait; never mind; Hangouts would be free anyway...