The employer give me the wrong gift card code!

I joined Verizon on NOV 7, the day there is an employee who said that if I join Verizon I can get a gift card for $150 for 4 lines so the total is $600. He gave me the code and the website where I can claim it. After a couple of times trying to claim it but it doesn't work. I tried to call the customer service and they said that this is the wrong code, the code he gave me will work when I purchase a new phone. The person on the phone said he should give me the one without the purchase of a new phone. The person on the phone was trying to find a different code for like an hour but cant finds any. This is basically a scam to make people join Verizon.