Looks like only my team got disconnected and we lost lp for it.

I was playing my last game of promos to plat with a friend. We were winning the game until we got disconnected at 19 minutes. My duo tells me all our teammates got disconnected and we were unable to get back on. After looking in on the match history, looks like the other team didn't get disconnected and they just rushed base and ended up winning which caused all our teammates to lose lp. Now it says I've failed my promos and am back to Gold 1 with 90 lp. There should be at least a loss prevention if not some kind of compensation.

This is the link to the match that I am referring to: https://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2904628773/247447210?tab=overview

Look at the match history and it is pretty clear that our team was winning until the last fight which occurs in 19 minute(which we also won) and from then on, it's just the enemy team adc taking down the turrets to claim a free win.