Voucher quick expiry

I traded vodabux for a spur voucher and that voucher quickly expired , I don't see a point in rewards expiring so quickly that we can't even use it , I sent an email to complaints and no reply , vodacom constantly phones me and thanks me for 36 years of loyalty but I can't even get a R200.00 voucher to enjoy for that 36 years .. 3 lines to be ported out when when term date is up