Need clarity.

Got a guy in champ select saying he only plays malphite either as, top, jung, or sup.

Well he gets to support me while i play tristana.

Early into laning phase the enemy jungler comes to invade bot side red. teammates (including malphite) see it and chase xin from bot red to our top side blue without killing him (probably chased for at least a solid minute, maybe close to two minutes).

come 5 minutes later malphite is roaming mid and im getting bullied (vs cait and janna alone bot lane). i get low hp and go to my tower to farm. malphite comes from river and engages them alone. stupidly, i went in to help him but we both end up dying. he starts flaming me saying "why are you fighting with double dorans vs cait that has more farm than you and bf". understandably its not my idea to fight them in that scenario, but when my support engages they will either flame you for not helping or for helping and dying.

after we had altercation about that scenario he said he wasnt going to support me. that "its not written that i have to support adc" and roamed map rest of game leaving me alone 2v1. needless to say cait farms easily and takes towers. she becomes huge and carries enemy team to win. towards end of game our jungler and malphite are blaming me for loss.

whats your thoughts on the scenario? i just dont think im in the wrong that game.