The questioners claimed that Abraham is their father and that God is their Father. However, because God the Father sent Jesus the Son, Jesus talked about how those who claim God as Father should love Jesus (8:41-42). Once again, even though the questioners can claim God as Father, they don't act like God is their Father.
Additionally, Jesus talked about how the questioners do not understand Jesus's words because they could not listen (8:43). It's not that they want to understand Jesus but couldn't; they could not listen because they focus on not listening. Kinda like how those who put their hands in their ears intentionally could not listen to what people are saying -- not disability, but refusal.
Furthermore, Jesus talked about how their father is the devil/slanderer/gossiper (8:44). Just like the other uses of "father", the usage of "father" is once again figurative (the devil did not literally give birth to the questioners) and refers to how they were heavily influenced. Figuratively, the devil/slanderer/gossiper is in a father-like scenario. The questioners' influencer is a big fat liar and even a murderer (8:44), especially since lies can lead to death. And since the questioners' main influence is a big fat liar, they do not trust Jesus, who was telling the truth the entire time.
Jesus closes off by saying how people of God hears God's word, so because the people don't hear God's words, they are not of God (8:47). Being of God is based on our response to Jesus rather than ancestry -- we can choose to trust Jesus and be of God (since those who accept Jesus are children of God as confirmed in Romans 8). But when we focus on lies, we can avoid the truth that sets us free, and that is no good. Yes, it's a hard truth, but it's very important to know the truth on Jesus setting us free, especially with the big problem on fake news that you're probably aware of.