Did not receive the offer and the store staff was rude when asked about it!!!

Since February 2020, I have been contacting verizon at the store and the customer service regarding an offer. We started a plan with verizon from November, 2019 where we bought three devices with a contract from verizon, iphone pro max. The said offer included, 500$ off due to the plan of starting new plan with verizon and 200$ off as we changed our carriers from Lyca from the total amount on the device for each devices. We were able to claim the 500$ off on the device as we would not be able to receive the devices without getting this offer. Coming to the second where the store staff particularly said they would credit us with 200$ off on each device after the first month of the payment. 

We went to the store , located at 1805 S Loop 288, to claim the 200$ on our devices in the month of March. When we reached the store the staff who sold us the devices was busy at the moment, so another person assisted us. When we inform him about the offer he says the offer is not valid after 2 months of the purchase of the devices and that we were supposed to fill out a form to reclaim it within those 2 months, but when we said we were not aware of said offer as the staff who sold us the device did not even mention it, he started arguing with us saying that it was our mistake that we did not ask about the link and that the other staff would have mentioned it.

If we are getting an off of 200$ for each device that is 600$ for 3 devices, would any person in his/her right mind would lose it if someone said to fill out a form for it? No, WE WERE NOT INFORMED OF THE SAID LINK! After few minutes of arguing he gives us the link and says try the link and come to the store the next day. So, we tried the link at the store itself and guess what, the link asks for a password and when we consult the same staff, he does not give us the right password and ignores us for the entire conversation and then at the end said to come to the store the next day.

As the issue started out in March, we were not able to visit the store due to Corona and we called the customer care for support. After 2 hours of waiting on the call they said they can speak to the store staff and that they should give us the offer as it was stated before.

It's been so many months, the customer care does not even pick our calls right now and we are sure the store staff would not care for this right now. Is there any way I can into contact with someone that can really help with this issue or does the entire stores work the same way?