I didn't say or even suggest that it would hurt. I simply suggested that if you weren't getting an answer here it might be best to ask Fongo directly.
FWIW I've had a World Credit on my account for several years. I bought the minimum amount ($5) just to make one international call. I've never made any LD calls since, yet the credit remains. (It's still over $4 today.)
I've never paid any attention to making at least one outgoing call every 60 days. I don't use the number very often. It's possible that there have been periods >60 days of non-use. And yet I've never gotten so much as a warning. So I can't be sure exactly why my account remains active.
Also I originally paid $25 to port the phone number in from another carrier. ISTR that ported-in numbers never expire regardless of how often they're used. Perhaps that's why my number stays active.
I mention all of this because it's very confusing, based on anecdotal information such as you'd get from posters here, to know exactly how Fongo determines what it takes to let an account expire or for World Credits to get consumed. That's why I suggested you contact them for an authoritative explanation.
Another option I forgot to mention is Fongo's own support forum: https://forum.fongo.com/I just wanted to see if anyone could clarify if an outbound long distance call was required. Wording seems to imply any outbound call - so I will contact Fongo and follow up.
But again, the most authoritative answer is most likely to come from Fongo directly.
veni, vidi, Visa