How did i get this elo?!?

I´m really frustrated! Last season i won 4 out of my 10 first ranked games. And i got to silver 4. And i stayed in silver all season though i dropped to silver 5. This season though i won 7 out of 10 games, and i was like: YES!!! But.. i got bronze 4, wich is really wierd. I mean i should at least have got into silver! At least! My friend was Gold 1, he lost 8 out of 10 and got gold 5.... My sister only won one game out of 10, and she got bronze 2!! Also im not the only one with these issues, i have heard complains from alot of other players that i have played with.

Is it something wrong with the system?

Plz if u have any similar experiance share it here, and contact riot. They should know about this. And sry for the bad spelling, i´m from Sweden so...

And riot if u see this, plz do something. I love this game, but this was really a dissapointment :(