There was an interesting psak mentioned as part of a parsha write-up on YWN..

Rav Yitzchok Zilberstein relates a fascinating legal query he once received. A young man entered a barber shop and requested that the barber give him a particularly good haircut, explaining that he was a groom who would be getting married that very evening. The greedy barber, aware that there were no competing barbers in the surrounding area and realizing that a groom on the day of his wedding would be quite pressed for time, informed his apparently helpless customer that the fee for the haircut would be double the usual price.

The groom was shocked and disgusted by the barber’s greed, yet he had no choice but to agree to the unfair demands. However, at the end of the haircut, when it was time to pay, he exclaimed, “Why should I pay you even a penny for this haircut? Don’t you know that I have miraculous hair that grows back to its original length just hours after it’s been cut? Your haircut hasn’t helped me in the slightest, and I shouldn’t owe you anything for it!” The astonished barber assured the groom that if he returned in the afternoon looking as he had before the haircut, he would happily give him another one free of charge.

The groom approached Rav Zilberstein with the following legal question: since the barber treated him unfairly and forced him to pay double the regular price, was he permitted to send in his identical twin brother (who hadn’t recently taken a haircut) to receive for free the second haircut which he was unjustly forced to pay for? Although the barber certainly wasn’t deserving of pity, and the groom’s quick thinking in his pursuit of equitable justice was quite original, Rav Zilberstein nevertheless wasn’t keen on his proposed method of being the barber’s “brother” in deceit.

It's a very interesting case and halachic discussion. As far as I remember the halacha, sending in the brother for a "free" haircut would not just be deceit but would actually be theft. What the groom could have done is he could have agreed to pay the exorbitant price for the haircut and then after the cut only actually pay the normal price. Had he done that, as far as I remember, the halacha would have protected him from being forced to pay more. once he paid the entire sum though, he is not going to be able to get his money back.