It can take a little time for the referral to get sorted. I had a slight delay with my referral. I used the app help section, use Wattbot and type message the team. Give them the referral information and they will get back in touch.
I followed this process and they got back to me within a couple of days. They confirmed they had received the referral and was ok, also that they would follow it up. Within a couple more days I received the referral voucher by email. Result 👍
Hope you get this sorted soon. Good luck