I am not sure if I did it correctly to get my $30 credit.

It might have expired???

If it's any consolation, the code TNORTHVR will give you 20% off most games in the Meta Store (except most of the ones on sale, but try it anyway, as it works on some of them) and the code hasn't expired yet.

Hi Maizilla​ 🙂

Maizilla wrote:

with the expectation of receiving $30 as told.

Who told you that, what promotion was it?

I suppose, you are not talking about the device referral credit, do you?