Never received $150 visa giftcard rebate

I purchased a Motorola cell phone and ported my number July 2018, yet my rebate never registered.  Initially there were some issues porting my number but eventually it was ported. I have been checking on the rebate regularly starting a month after the account was activated. The account is still open since I keep missing the hours of the award center and have been told to wait to cancel. The terms of my obligation have been met for over a year so I am not sure why I have to wait to cancel the line, paying for a service which I'm not using. And I certainly do not understand why I do not have my giftcard.