REFUND ME or transfer credit to my son's number ***

i keep loading vouchers and have proof of purchases from pick n pay and discherm, my wallet is now R400. when i checkout neither my card or UberEats credit allow me. Popup error is always "Please try another payment method, new user promotional codes are not available for this account and the trip will be charged at full price". AM so tired since January, in app team and Twitter are overlooking my complaint!