Finally got it. I called again to sales department and they told me that I will get a coupon code of 250$ (which is exactly that 6% of my purchase) after 3-5 business days. I got it. I used it and everything worked out fine. 
When I was purchasing my PC, monitor and all the necessary accessories it was clearly saying that I will get a 6% in rewards if I’ll finance it. So I did. 5 days after purchase I didn’t see any rewards even in pending. I called to dell support and they told me that I would need to wait till everything will arrive and rewards will come few weeks later. So I did. I waited few weeks after my stuff arrived and now no rewards and no pending rewards. I had to call to customer support again and now the lady on the phone told me that I WILL NOT get my rewards! She told me that it was my fault and I not supposed to get any now and that I can return the stuff if I want a refund. I’m sorry, WHAT? I have been mislead and now it’s my fault and dell doesn’t want to keep my money? I like the stuff and I want to keep it. But also I want to have my promised 6% in rewards. How I can get them?
Didn’t get my rewards