Why must I pay for your mistake???????

Be aware of VIRGIN ACTIVE promotions. They offer you contracts with 1st month for free and debit orders only going off from 2nd month of contract. Than they email you your contract and…. surprise surprise NO 1st month free. When you point that out to them, they confirm in writing that 1st AND 2nd month are free. However, debit order goes through in 2nd month instead of 3rd month. When pointing that out, all you get is an apology “we made a mistake” for which I now have to pay for. Why is it that VIRGIN ACTIVE members always have to pay for mistakes VIRGIN ACTIVE staff makes??? Honour what you said and make the person who made the statement in the email pay for this mistake