It was the local ekklesia they met with. The Catholic concept of "church" is unknown in scripture.
So wrong.
Christ wanted His Church to be one.
“I appeal to you, brothers, in the name of our Lord Jesus Christ, that all of you agree with one another so that there may be no divisions among you and that you may be perfectly united in mind and thought. My brothers, some from Chloe's household have informed me that there are quarrels among you. What I mean is this: One of you says, "I follow Paul"; another, "I follow Apollos"; another, "I follow Cephas"; still another, "I follow Christ."1Cor 1:10
One. Not many.
Christians cannot be “perfectly united in mind and thought” when they have different beliefs on, say, the necessity of water baptism, while others believe “This is my Body” means “This is a cookie”
God bless in your journey to the truth.