WARRANTY

I had an issue with a laptop while under warranty. Tech support remotes in and swapped out some drivers and stated "if this does not remedy the issue, it means it will be hardware and not software and more than likely we will swap out the motherboard". I received a "notice to CLOSE THE CASE and responded that I was still having the issue. I then repeated my email request to not close the case and STILL NO REPLY from any Dell department. I sent a read request and received a READ statement an that shows me the email address I had was active. I then called and asked for a supervisor who would only state "it is past warranty" and then HUNG UP ON ME. This is a disservice and no one should be treated like that. I am a loyal customer for over 15 years. I have spent countless hours trying to get this resolved since it should have been handled in a timely matter and I would not be in this position. What can I do ?