I've just been contacted by a seller that they're cancelling my purchase. The thing is I've bought the thing using my CC with installment and its probably going to take a long time for the refund to be processed. Is there a way to complain to 11 street about this and get compensation for the trouble?

yeah, my bank already clears the transaction.
but still, I was surprised that sellers in 11street can cancel buyer's order for whatever reason they like and 11 street will just automatically approve it. I get no compensation and no choice on the matter. Funny thing was, the seller gave reason that the pricing for the product was typo error, yet 3 days after my initial order was cancelled, the same price still posted for the product. Quite unethical behaviour.