PROMO VIRTUAL PREPAID CREDIT CARD

I just noticed that my T-Mobile bill includes a $20 credit labelled 2022 HINT P11. When I searched the web I found this thread. 
 

I “think” this is how I am getting my gateway for $30 rather than $50 per month.So the “virtual card” is just an internal system T-Mobile uses to handle special credits during promotions, it seems. 

The OP asked whether this would affect credit ratings. I would assume it wouldn't, since it is the equivalent of a gift card you receive at store sometimes when you return an item. No credit check is involved. It is just a way of giving you the cash, but restricting your use of it. 

Just guessing, but this would be a way to handle things if T-Mobile has to charge tax on the total cost ($50/month for my gateway, say) but wants to reduce your cost by $20/month. The $50 is the cost, tax is based on the cost, and then this promo credit is applied internally as a payment. So on the bill it can list the cost as $30 but the computer system can accurately calculate the tax. 
 

I don't work for T-Mobile. I am just a customer who has tried repeatedly to make sense of my bill. When we signed up we traded in phones and got "free" upgraded phones. That included about five tricky booking moves that I still can't explain, but that seem to be similar designed to reduce the price but still handle taxes correctly. 
 

Hope you enjoy the service. I LOVE the T-Mobile Tuesday prizes, especially the physical things they give away with their logo.