I will love to let you know that in the crypto world referrals doesn't give you more cryptocurrency or increase the money invested... The only way is by either buying at a low rate and selling when its rates spikes higher or by hoarding it ........ *(you guys should wake up before them snatch your bed and pillow leave you for ground).
Any crypto broker that's doing referral to earn cryptocurrency, I don't think they are in anyway affiliated with Blockchain, try and make your research before investing your money into anything.
The thing they are doing in any referral scheme be it cryptocurrency or monetary based is robbing Peter to pay Paul or vice-versa.....i pray when they fold up you don't get caught up.... You may have made a lot from it but if the person you introduce doesn't and he/she looses his/her money You will be reported to the necessary authority for questioning.... Just so you know.