my hero rotation is glitched

about 6 week ago , i started the game . arhi was free and i used her for a week, it then change and gnar was free who i played howver the hero rotation changed after 2 days , i thought it was because of a update but it not . for 4 weeks I have had the same non-changing hero roatation that refuse to change. I thought the recent up date would fix it but I has no. I'm really confused at what is happening here. the current heros that have been avalible for the four weeks is brand,caitlyn,druis,illaoi,miss fortune,morgana,sona,nami,nocturne,xin zhoa.