False promise on vitality subscription

Vitality advertised they will offer 3 months free subscription. I am an existing vitality client from last 6 years and for technical reason no payment made to vitality and subscription ended. I lost all the benefits and now i have rejoined and while joining they confirmed that the first payment is only after 3 months. Now vitality denying and deducted the first instalment straight away and response is I am not eligible as old customer