Helllo Guys

My O2 homespot contract ends next year September. But for the last two months i am getting 5 mbps speed on 50mbps connection. Is there any way to cancel the contract before next year September because although i signed a contract for 24 years O2 lied that i will get 50mbps speed. They are literally lying to customers . I have tried their methods restarting the router , pulling out the sim and inserting again but this doesnt help. Can i legally get out of the contract before the 24 months if i am not getting the service O2 stated?