Am I getting scammed by Xfinity mobile?

I started a chat a couple of weeks ago to see if there was a new promotion I could get on my internet services as my current promotion was running out.  The chat agent was able to help me out but also mentioned I could move my mobile service over from my then provider to Xfinity and they would apply a promotion that sounded pretty good.  I asked about what would happen about the balance I owed on the phone I had with the provider I was under at the time and the agent said that they were willing to offer $500 outright to help me pay off the remaining balance.  I asked for this in writing but they basically said I would hear from someone via email about setting up for that.  I agreed and set up the move of my mobile services.  A day later, no word from any customer service. 

I called to speak with an agent and the best they can do is say that there is a promotion where you can get $500 for trading in your phone.  The first chat agent I spoke to said nothing about trading in.  I was told straight up "We will give you $500 to help pay for your phone."  That's it.  The agent assures me they will escalate and I will hear back within 24-48. 

Two days pass and I hear nothing.  I call again and I am told something about signing up for some other promotion that deals with trading in through the timetoswitch website.  I note that if I go through with this, it's not going to get approved because I am not trading in my phone, just trying to get the $500 credit I was promised.  I asked to escalate again and was assured I would hear from them within 24 hours.  A week goes by since I had other things to attend to and as of this writing I am on the line with another agent who I believe will try and get me off the phone by promising me more lies.  Did I just get scammed?  Am I going to have to kiss this $500 goodbye?

Edit: After 1.5hrs on this third call, I was told this matter was escalated to their level 3 customer support and I have to wait another 3-5 business days to get a response.   I once again got assurances that I will get some comms in that time frame.  At least I got a reference number this time which calls into question what the first two calls accomplished.  I am super-frustrated and I do not believe the poor agent that told me I have to wait for another length of time.  I fully expect I have to waste more time and call yet another person who will probably lie to get me to hang up the phone.