Ulleh is NOT greek, it's actually in a Lebanese Arabic accent, it is most definently NOT just a random saying. it's actually a slang way of saying "you" equivilent to "man" in english. In the Iraqi Arabic accent it's actually pronounced "willeh" or "willak (short "lak"). It's mildly offensive to elders or people of a respectable status within the community.

the thing that you don’t have when you’re phones percentage is over 20

Something greek people say after every sentence. It is just some random expresion.