Not sure if bugs or BS

I jsut got out of a game laning agasint garen, as darius.

Was a rough lane, he would constantly go ham and dive entire waves, but woudlnt stick around long enough to fight. Until he got phage, then suddenly he stopepd taking damage, im not exaggerating either. He went all in on me, i hacked away at him with everything i had, it was post 6, i had a few poitns into E to ignore his armour, but he jsut didnt take damage, i had about 50 more AD then he had, and even got 5 stacks on him, but when i ulted his HP bar didnt budge, he went ot hide at his tower for abotu 5 seconds and came back out at full HP.

And it got better, for no real reason i coudlnt heal off him with my Q, and he woudl constantly ignore damage and stacks form it.

Now i know that when in handle range he doesnt get a stack and takes less damage, BUT when hes CLEARLY in yellow range without his W up and my Q does 400 damage why isnt his HP bar moving? why isnt be bleeding? and why isnt his heal turning off?

I wish i had a replay i coudl rewatch to show what happened becuase it gets even better. we both completed our cleavers, he finished his first and was about 10 AD behind me, then i finished mine and was suddenly 30 AD bnehind him. and he had built NOTHING but tank after his cleaver. but what was even worse then that was he staretd the game with around 60 armour and 54 MR. thats jsut not possible, its not. he woudl have to decicate ALL his runes and masteries into JSUT armour OR MR to get those kinds of numbers, and even then im pretty sure it cant be done.

I dont normaly run around accusing players of cheating, but its that or the entire game was bugged the f*ck out.