The vitality PNP offer not available to everyone

I recently signed up to discovery and saw the offer to get a pnp voucher should you wish to sign up to Vitality too. Chatted to Karina and she said i will get the offer should i sign up. I sign up only for her to get back to me and say that because she signed me up and I didnt sign up through the link I would not now be eligible for the pnp offer. broken promises and now I have to chase getting my vitality cancelled as she is unable to assist just so I can resign up for the same thing online. Useless!