Riot stole my penta

I was just playing a 5v5 ranked game as Vladimir; I was huge at this point in the game, about 24/9. I dove the enemy's base while my team went for dragon. I killed 3 of their team at the inhibitor turret for a triple. At their Nexus turrets I had the final two very low, I killed the first, no Quadra but I got "Rampage", killed the other.... Counts for a double.

The time span between the first three kills and the other two was well under 10 seconds, I wasn't awarded my pentakill because of the killstreak callout taking precedence I assume.. It would be nice if I could be credited the pentakill, or that this issue could at least be looked at.