$250 gift card for being new customer

[LenaALena]

We received a $250 gift card upon installation of TV, phone and internet service and were told it could be applied to our bill.  We don't really need anything from the Verizon store.

When we try to use it we have to give our verizon cell phone number.  The problem is we don't have Verizon cell phone service.  We can't get ahold of a human operator.   

How can we apply gift card to our bill?  

Thanks