When Kucoin has already confirmed that the funds have been released from thier side then you will need to contact ByBit exchange. If they are not helpful or are clueless then you should comeback and update this thread with their reply. This is the first time I have read of such a problem. If you have entered all the details correctly then they will be able to locate the funds credit your exchange wallet.
Bybit has sent me the refund TXID and it is the due of kucoin to the coins back to me. But kucoin is saying that I should pay 40$ which is abnormal.
Whom exactly are you talking with and from what source? Because asking money to do things before they do it, is excatly how scammers operate.
I never ever had to pay anything for forgetting to add some memo and asking help from an exchange i send it to. And it's not like kucoin has anything to do with this issue, your money is not in Kucoin after you send it to ByBit. They even said that themselves.
You should deal with Bybit directly. Nothing about this sounds right.
If that Kucoin admin is indeed not a scammer, he / she is asking money from extra work you could do for yourself by contacting the team's discord and other ways that i provided. I don't think asking your money around from other exchanges is even on any help admin's or helpdesk's job description.