[2020] My Rank Got Reset After 280+ Ranked Matches

I played 280+ Ranked matches this season, majority of those being played with friends I trust. To compare, last season I played 857 Ranked matches, majority of those being played by myself. I played about 35 of those 280+ Ranked games by myself, but the overall majority was with friends, with the combinations of friends sometimes. I hit Platinum III for the very first time this season, which was very rewarding for me because I was a hardstuck Gold player most of the time I've played this game. I would occasionally get an MMR rollback time-to-time as I logged on. I was either gaining, or losing MMR. Yesterday when I logged on I found myself losing 89 MMR, the day KingGeorge loses 554 MMR due to a rollback. Today I logged on to find my Rank being reset. This was very frustrating, especially after knowing that I played 280+ Ranked matches for basically nothing. Something did happen about 2 weeks ago. I was playing with some friends, and a person we brought in. After several matches, I find out that the random we brought in was a cheater. I chose to report the cheater and decided to stop playing Ranked with him. Today the cheater was banned, and this is the only reason I think I got my Rank reset. However, that doesn't explain the fact that the friends I usually play with did not get their ranks reset though, they just lost MMR. This makes me beg the question: Why did my Rank get reset? Is this a bug and will I be able to get my Rank back or receive some form of compensation? This is very frustrating for me.