Why isn’t there an error message saying you can’t transfer unless it’s bitcoin to bitcoin?
Because BTC and BCH use the same address format. Your address (or to be more specific: priv-/public keypair) is valid on both chains.
The exchange can't know you used a BCH address to recieve BTC, since its a btc address too.
Usually this isn't a big deal since you can just import the private keys into your BTC client and your funds were available.
But since you were withdrawing amount to another exchange (without you having the control of the privat key), you have to contact polonienx.
They are able to recover your funds, but this will probably cost a small service fee (if they even going to do this for you, they could just keep the 5k).
I hear you, neither have responed to my question. Why have support section, if urgencies go unanswered.
Am I screwed? Is my money gone?
No need to get cocky 12 minutes after posting this thread. Its your personal fault. You have to look at what you are copying and not just blindly copy/paste everything you can click with your mouse.
Honest altcoins have their own names, and their own address prefixes (or even entirely different address formats).
^This.