Received email stating undeliverable item, tried to contact company

I received an email stating my walmart giftcard was undeliverable and my points were refunded. I tried to email stating I never received it and that my post office stated there is now a change in how the address must be on any mail (we have to have the P.O. Box on it, otherwise with the change in the local mail distribution center they will not get our mail to us). I received an unhelpful automated answer at that time. I still want the reward that I stayed up to get as soon as it became live! Can I still receive my reward?