FNB Ebucks team not helpful

FNB Ebucks team offered me a reward, that i qualified for and now they give me run around when i need to activate and use the voucher, their staff are so *********** that they have the audacity to tell me that if i cannot redeem the voucher there is nothing they can do as they have already escalated my query to their senior, the same senior has since sent me an sms to say i can access my voucher on the App but it is still not there, I'm so ****ed off im even thinking that this could be a **** form such a big bank. The whole Ebucks team is failing to resolve my issue