Hi Arthur, the message you received may be a system error, you can contact MTN support to know if the offer is genuine, they will help you to receive it if MTN is giving such...
I bought a Mifi device from your shop at Ikeja City mall
S/N 320513884549
IMEI: 867462052329632
and MTN line 08104170681
and I was told I will get twice the data I purchase...
