I have had that same problem with Poloniex. I decided to move to OpenLedger. The volume is low, but as more people move over, it will get better. It too has problems, but mostly that not as many coins are supported and the volume problem.
Plus there is the benefit that it is a Decentralized Exchange (DEX).
Here are some others. -> https://steemit.com/cryptocurrency/@diggndeeper.com/moving-to-dex