Promotion bug

Hi i am a silver 2 player. I just recently got into my silver 1 promos. I lost a ranked game and then won one straight after, the weird thing is that after i won that game the promotion to silver seemed to have disappeared. I thought this was some strange visual glitch so i thought nothing of it. However after i won my last promo game i didn't get promoted to silver 1 instead went back to my promo's starting again. This strange bug is really annoying as i was trying hard to win the last 2 games of my promo's, only to start again... Anyone with the same problem please help Thank you