I had a similar experience with an Exchange. After the Bullrun of 2017 and 2018 i had some of coins parked in Polo... I didnt log in in a while and after a few month i came back, just to see they had delisted a coin.
Well first of all, sure my part was the negligence to hold them on an Exchange after all. A total no go.
But the reason i was really annoyed was, that the exchange didn´t send any E-mail or information out to its customers.
That was a scatchy move.
I since then abandoned the exchange. I use coldstorage and just move coins for trades to an exchange i "trust".
Its time for some good DEX.
Greetings
I hope you did not lose much on that one. I heard that Coinbase is being regulated by the government closely, but because of that, they are probably more responsible for their customers' coins. The biggest con is that customers will lose their anonymity.