You guys are assuming he didn't tell her anything. In fact, it was already apparent Stefana had precedence over Jovana back in 2017, but the absence of Milena for much of that summer masked that fact (rest assured, not to Jovana herself, who would have been all too aware of the situation). However, in 2018, that could no longer be avoided, and it became clear to everyone that Jovana is now a bench player. Only THEN did she start to make trouble, and to conveniently "pause for a year" (after only 4 years in NT!). So this is not something that has arisen only this year.
If I may conjecture, I think the reason that Stevanovic is acting with this much entitlement is that, AFAIK, she is only one of 3 players in the history of Serbian female volleyball to immediately get starting position the very first year in NT, and to keep it beyond that first year (the other two are, of course, Boskovic and Mihajlovic, although Brankica would probably not have been the starter if everyone was healthy in 2012). Furthermore (and this is an even bigger conjecture, which I freely admit might be reaching), the year she joined, 2015, is the year Serbian NT really exploded, and started regularly getting medals from all the big competitions. That may have even further inflated her own self-importance.
In this, she stands in sharp contrast to her rival Stefana, who spent her first 9 years in NT being almost always the 3rd MB. She didn't mind, and patiently waited for her opportunity to become an established starter, helping in the meantime from the bench, which should make one even less sympathetic toward Stevanovic's antics.
yeah.. after fabiana and thaisa, the 2017 mb game was between carol and adenizia. But bia had opportunity and stepped up her game.
In 2018, ade and bia was starting. Brazil was the best blocking team in vnl.
In 2019, ade rested. Bia and mara came. In world cuo mara and fabiana started.
Well, the analogy was that. The position was not given to you permanently. You need to strive very hard to maintain it. In case of brazil up and coming players were met by returned of seasoned players... same goes with serbia...
I remembered maja alesksic (not sure if spelling was correct) making the opportunity given by the serbia nt... this continued in the world cup. And milenkovic and bjelica presented self and acted for serbia when their starters wanted to take a leave.
As for serbia 3rd middle blocker you should not be accustomed of your position really. Sad!