LOST PROMOS BECAUSE OF FAIL TO SELECT CHAMP BUG WHEN I COULDN'T LOCK IN

I joined a ranked solo/duo match queue and got in champ select, but I couldn't lock in my champ or change any spells, runes, and masteries. The countdown went down to 0 and got stuck there. I still tried spamming lock in button, but still didn't work out, so it dodged the champ select. I tried doing it again and the same outcome happened. My internet is working fine and it's really fast too, so I don't think this is an internet problem. This bug caused me to fail promos :/ FIX IT RITO. This isn't the first time that this happened to me.