There is no way to reverse but there are all proofs that you sent and when.
They have to answer you and give you the proof that they sent (or not) the other coin the address you provided.
People are having trouble with exchanges support these days...
Everyone better test/verify with small amounts as if there was no support..
Shapeshit has been a reputable establishment, I think they will do their best, make sure they do not forget you.