Terrible Service

I purchased tow mc Donald's vouchers with my MTN yellow bucks, I proceeded to attempt to us them at my nearest store only to be told that the voucher is invalid. I called MTN yellowbucks office and advised that the voucher's are invalid on 22/03/2022 . I was advised that new vouchers would be sent to me with 24 hours, i called again on the 23/03/2022 was advised that this was escalated to management and that Mapiku would call me the next morning, 24/03/2022 still no call or vouchers received, I called again spoke to Morgan who is there manager, Extremely rude and talks over me, he cannot commit to a time frame and advised me I should proceed with posting the query in the media because he cannot assist me. Absolutely disgusted by the level of service I have received from MTN, I definitely will not be renewing my contracts with you guys .