Internal Error Occurred, cost me promotion

2 times in the past week I have been on a best of 5 series to promote to silver, and both times I am 2 wins, 2 losses, and my 5th game, it will not allow me to select a champion. When I try to click on a champion, nothing happens. The clock ticks down and I see people typing, so I haven't disconnected, then I get kicked out of the lobby and I get a pop up saying "An internal server error has occurred", then I am banned for 6 minutes, and lost both promotions for the same reason. This is really getting annoying.