Matched betting

Matched betting is actually not gambling. U Matched betting (also known as back or lay bet matching, arb betting, or double betting) is a betting technique used by individuals to profit from the free bets and incentives offered by bookmakers. It is generally considered a risk-free bet as it is based on the application of a mathematical equation rather than chance. A typical return for a matched bet where the stake is returned is 85%+ of the free bet offer amount, and 70%+ where the stake is not returned. So for example, if you see an advert for a bookmaker and they are giving away a £10 free bet - on average, using the techniques and with the help of software, video guides you will be able to 'unlock' £7 of that free bet as profit. That's real money that you can withdraw and spend on whatever you like. Its a risk free and not gambling. Is that haram in islam??