"The contract is binding on both parties except for instances of a Pricing Error."
""Pricing Error" is defined as a misquote by LCG where the price quoted materially and clearly deviates from the prevailing market price (or the forward calculated market price) at the time that it was quoted. A Pricing Error as defined, but not exclusively, is a Bid price or Offer price which varies above or below the prevailing mid-market price of the underlying product by more than the size of the quoted bid/offer spread of that product. For example a bid/offer quote by LCG in the UK 100 Quarterly contract of 4804 – 4808 when the correct quote should have been 4797 – 4801 may be considered to be a Pricing Error as the LCG Bid of 4804 is more than the quoted spread of the product (in this case 4) away from the mid point (4799) of the correct quote."
"An email or on screen confirmation of a Transaction that does not accurately reflect the relevant underlying market price at the time when the trade was made either over the telephone, or via an OTP or a DTP, does not entitle the customer or LCG to enforce whatever has been inaccurately recorded in the contract note and is likely to constitute a Pricing Error."
Of course , he could also ask for a trade reversal if he have traded on a wrong price and lost money .
hard luck