Disclaimer - While I'm obviously directly addressing the OP, I want to make it clear that i'm not trying to insult anyone here, merely point out the truth. EVERYONE has made these mistakes at some point. Most still do.
Razer build quality is pretty poor for the price on most of their products. EVERYONE knows that.
MOST of their products are also over-hyped overpriced cheap common hardware in fancy cases. (for instance, all of their membrane keyboards. You can find any $6 keyboard and slap on the same shell and you have the same keyboard. There's nothing high tech, magical or "gaming" about it).
That all said, they aren't horrible monsters set to destroy your computer and give your broken products.
It sounds to me like you have fallen victim to two problems
You bought junk, thinking it would be good. It doesn't matter what company you had bought something from, you would have likely ended up with the same result. Every company produces junk and markets it as gold along aise their actual useful products. It's your job to inform yourself as a consumer what the signs are for spotting actual features vs over-hyped, gimmicky, or even broken design factors marketed as beneficial features.
Example: The Megalodon.
"surround" and "usb" audio is rubbish. Be it Razer, Logitech, Steelseries, Triton, Turtle Beach, Psyko, Bose or any other manufacturer, it will still be trash. Yes, Razer is at "fault" for producing and marketing said trash, but if they didn't, it wouldn't stop everyone else from doing the same thing, and it wouldn't have stopped you from buying the same trash from another company. You need to not buy into the marketing because EVERY company will try to put the same spin on their useless junk.
2) The assumption that your computer itself is without flaws. Fact of the matter is that almost no one has a perfect computer build. The very nature of the PC market ensures that there will be times where incompatibilities go unnoticed. Everyone's computer has some small (or perhaps big) quirks that may or may not make themselves noticeable at some point, its simply the price we pay for not all running nothing but apple software on Macs with pre-approved hardware configurations.
Example: Your USB controller.
It appears, as many have stated, to be somewhat faulty. It would explain why you hare having identical problems with identical hardware. Personally, I burned out several flash drives and returned them all as defective until I realized one of my USB ports was shorting out and killing them on an old build many years ago. Don't forget that your computer can have it's own issues to address/work around. You don't want to end up killing your flash drives forever when all you have to do is plug it in the other port instead, if you catch my drift
Now, in your particular case, there are some tips I should point out, just because I know these things from personal experience and research:
1) The mamba WILL work without replacing the battery. Just remove the battery entirely, plug in the usb, and turn the mouse "off". If that doesn't work, the only plausible reasoning is that your usb controller is failing it's job yet again. Try disabling selective suspend and associated power savings features on your usb controllers! It might just save you a lot of frustration.
Oh.. and they sell replacement batteries for 20 bucks... its not ideal, but you cant really complain either. Battery's never last forever, you knew that going into it.
2) Stay away from "gaming" keyboards unless you ABSOLUTELY MUST have dedicated, pre-attached macro keys. Why? There simply is no such thing. If someone is marketing a keyboard for gaming, chances are it's a gimmick to sell you more trash. You want to press WASD and 2 other close keys at the same time? Forget Razer and Logitech's "Gaming Cluster Anti Ghosting Technology" and just get a keyboard with 6+2KRO via USB or NKRO via PS/2. Hyperresponse keys? More nonsense, get some mechanical switches if you want an actual improved key pressing experience. Macro/"G" Keys? Just map some yourself via software to a number pad, or pick up something like a Logitech G13.
3) Stay away from "Gaming" audio products, "Surround" headphones, and headphones/speakers/mics that use USB connections. If you really want to produce the illusion of multi-channel audio via headphones, use a pair of good stereo headphones with a large soundstage and use a decent quality sound card to emulate the surround via CMSS3D or similar