This is a really serious situation, it is annoying when simple things like missing a memo tag end up causing so much trouble. Bybit has done their part by giving you all the details to get your USDT back though..
The fact that kucoin confirmed the coins are with them and asked for $40 to process the refund is fine but if they are stalling and still have not sent the refund link they said, then that is really unacceptable. Maybe you should try to follow up with their support team again and disturb them about the situation.you can also check if they have a way to get the case to a higher level of support team or even through their social media acoounts, hopefully you get a response soon