Please Riot Fix This!!!! I Really Would Like To Play With My Friend...

For the past few week i have been unable to play with my friend on the rift. We can play Team Fight Tactics but not the rift. My friend is unable to connect to the game when we play together we tried even in custom games my friend can not connect. But if we play our separate games everything is fine. We have talked to a live agent but still haven't heard anything back. Please someone respond and let me know what can be done about this.