Only part of cash back received

I entered for the Cape Summer Trail Series® 2018, one of the events on the Discovery Race Calendar and therefore eligible for 50% cash back on the entry fees. I submitted my results to Discovery after each event and was awarded my Vitality points. Although the last of the 4 races took place in February (and the organiser insists that they provided all results within 48 hours of the race to Discovery) I have not received the 50% cash back on the entry fee of R665. The only amounts I have received to date was R95 on 26 February, R92.50 on 28 March and R92.50 on 25 April. I have tried following up with Discovery, without success (Query Logged - ********** 089 - Team Vitality - Team Vitality -WRefNo# ********** 730#- -MailRef# ********** 350#-)