Bet365 complaint: Bet credits

I was sent an offer to my mobile number to bet £10 on horse racing and once the bet was settled i would receive £40 in bet credits.
I read all the small print and it says if you was sent the offer by text message or email you would qualify.
Ive made the bet and bet365 are now saying i dont qualify.
This is wrong as its getting me to bet by enticing me with a good deal and then taking the offer away.
Ive not bet on bet365 for a while as i cant really afford it but the offer seemed to good to miss so i made the bet.
Getting people to gamble by offering good deals and then taking them away after they have had your money is wrong and very irresponsible for such a big company.
This needs reporting and stopping.
It might only seem a small amount of money but iam willing to take this to a solicitor if need be
Kind regards
Darryll Rigden