If they say no, can I still use SV to get BCH back?
Sorry to say but it's not possible since BCH also irreversible crypto-currency. Only way I told you convince exchange to recover for you. If you had hold your private keys then it was possible very easily. But any exchange will never give you private keys.
Can you please let me know if there is a way to get the BCH back if I transfer BSV back to electrumSV wallet?
I told you that whatever wallet you are using doesn't matter. But you should have private keys of your address where you have sent fund. If you have private keys then you may spent your coin by using electron cash as I have said above. You may follow above instructions.
By electrumSV wallet did you mean electrumsv.io ? They are only allow use BSV, so you have to use some other wallet like Electron Cash.
The only cryptocurrency ElectrumSV supports is Bitcoin SV
Unfortunately btcmarkets doesn't provide retrieval services.
While we understand that this can be a stressful experience, BTC Markets does not provide a Coin/Token retrieval service.