Terrible Customer Support, I have been getting strung along for weeks with no help.

They're not stringing you along.  

The answer is in your post:

"customer support says I can't get a refund or replacement anymore because it falls out of the 30 day period "

When you request a replacement system, it does not reset the time clock.  

You may be able to tweak the battery settings for lower brightness, cut out the network when it's not being used, aggressively manage the CPU speed -- but that's about all you can do.  You haven't mentioned the type of screen you have (FHD or 4K), but the 4K screen greatly reduces battery runtimes -- it's not inconceivable that 4-5 hours is all you can reasonably expect, and that's with intermittent use and all the settings mentioned here previously set as aggressively as you can.

Oh yeah, I had a similar problem, they got my address wrong but started my warranty anyway even though my laptop was lost in the mail. I tried every department, but no one would change the date to when I actually received my laptop. Its a saga that went on for months. I'm so sorry you're going through it as well.

As to your battery problem, you might have a bad computer or bad battery. If you want to try things on your end, there are a bunch of videos on YouTube on Debloating Windows 10. From turning off microsoft tracking everything you do, to turning off apps running in the background, there seem to be ways to lower the load Windows 10 takes on you system performance.

But it could also be your laptop's fault.

I started requesting a refund while still in the 30 day period from the original invoice, but customer care did not get back to me or help me until AFTER the 30 days were up. They have been stringing me along. That excuse also doesn't account for nobody responding to their emails, my cases being closed out of nowhere with no follow ups, etc. Its a 1080p display. I'm always on better battery settings. I keep unnecessary programs closed. There is no way that it should be lasting 3 hours at most. I've literally contacted technical support and they themselves told me that there was an issue with the battery.

Glad to hear I'm not the only one that had to go through this. How did you eventually get the issue resolved? They keep repeating the same thing about the laptop being out of the 30 day return period, even though I initially had been trying to get a return within the 30 day period. It seems to me with the outsourcing of calls to Indian call centers, nobody actually takes me seriously or understands me. Wish I could get in touch with someone from the US/UK.

I wasn't able to get it resolved. I called, chatted, and emailed with every department I could find. No one would change my start date of the 30 day return window. In reality Dell doesn't actually have a 30 day return policy. It's more like a several day return policy. They were kindly willing to swap or repair the broken laptop they sent me, but getting my money back was something I could have only done within the couple of days left on my refund window. I now own a Dell laptop regardless of weather or not I'm happy about it, and if something goes wrong I'm now given less than a year with the basic warranty for repairs/replacements. I might not have bought this laptop had I had know.

Less than a year of warranty support ?  That is really different from my experience.  I have gone through 3 exchanges with defective XPS 9500's and on all the units, the warranty expiration dates are 13 months from the 1st day I boot up the machine. 

Yeah, I ordered my laptop on August 24, I didn't receive a working laptop until mid October, but my year warranty and 30 day return started September 3rd. I wish I had your experiences. It seems like a no-brainer to error on the side of 13 month warranties and fresh start dates, if you want to have a loyal user base that helps you grow your brand.

Hello. I have not heard back from you yet and shall be temporarily archiving the case at our end. Do write to us in case of any additional queries. We would be happy to assist you.

I've been buying systems from Dell over a decade and have never seen such poor support. This will be that last system I purchase.