The conclusion is this:
jaboticabas are pretty much all mislabeled...and that goes for M. cauliflora..which is actually M. jaboticaba (sabara) 90% of the time.
In this case, the fruits of M. floribunda (the true one from brazil/south america) are probably not the ones you remember eating.
It was a species more like the one pictured by TREESNMORE.
Rumberry/Guavaberry = small myrtaceous fruit, probably in the family of Myrciaria, Plinia, Syzigium, or Eugenia.
So if u can get a picture of the leaves of the tree u like...then u will have a better chances of reuniting with your long lost fruit.
Hope you get to taste the fruit you are looking for, once again...and soon!