Overbuff Link

Ive been struggling to get out of gold and stay in plat for several seasons now, even as Ive improved by leaps and bounds as a Mercy player. I seem to always be put against smurfs and paired with very low skill players, which I understand is how everyone thinks when they are stuck in a rank.

But at the urging of a friend, I checked my Overbuff stats and it puts me in roughly the 75% of Mercys, which is about Diamond/low Plat. Yet I continually fall into really unbalanced games and remain stuck in Gold. The only conclusion I can come to is that my MMR heavily skews the teams I get and face against, because the game essentially thinks Im smurfing.

How do I reset my MMR without being an asshole and throwing? How do I solve this problem?