The bug report forum is intended to report issues with the game itself and Blizzard does not provide direct responses here. The problem with live stream rewards is that it involves an outside promotion system that uses your BattleNet account which the Overwatch Development Team is not involved with short of setting up the skins in the game (which we know that part works fine).
When it comes to earning rewards, you really do have to be vigilant and ask for help when something is not working right while there is still time to make it up. Obviously this is not easy with a tiny promotion window with the grand finals. I maintain key troubleshooting on my streaming rewards guide which is pinned in the #general-discussion forum, but those steps are only usable if there is time remaining to keep watching (presuming any problems are fixed on your end). In the end, a very high majority of eligible players did receive their rewards from the Playoffs and the Grand Finals this year, so unfortunately there is little that can be done from the very few cases that I am seeing here.
Again, at this point, your best option is to wait for another opportunity. If you have feedback about how Blizzard handles live stream rewards you can post that feedback on the forums, but be sure to do it in the #general-discussion forum where it is more likely to be reviewed by the Overwatch community managers.