You say one thing, she says another. That's just how Rika is. There's no way I can win an argument with her.
Literal
'That-way [if-ば] say, this-way [quotative-って] say'. Rika [exasperated-ってば], such a person is. Complaint [possessive-の] mutual-saying [locative-で] can-win reason not-exist.
ああ言えばこう言う is a well-known set phrase for someone who argues back against everything you say, with a counter for every point — literally 'if you say that way, they say this way'. The こーゆー here is a drawn-out colloquial こう言う. 里香ってば uses the exasperated topic particle ってば, conveying frustration with the named person. 勝てるわけない (the potential of 勝つ + わけない) means 'there's no way (I) can win' — ~わけない is the colloquial emphatic negation of possibility.