The poster above is right. Sanitation is the real issue, but I think there's even more to be concerned about.
Plastic fermentors pretty much become useless when you scrub them with an abrasive brush, because all the tiny scratches (even if you can't see them) harbor bacteria and it becomes nearly impossible to effectively sanitize. If some micro-scratches are able to turn a fermentor into junk, I'm pretty sure a rough, glass hole/crack will to. The beers you make in it are very likely to go bad - it's the one piece of your equipment that beer in its most vulnerable stages stays in contact with for an extended period of time.
Also, I think it's extremely important to mention that you NEVER buy plastic equipment used - stainless steel and glass are (usually) fine, as they can generally be sanitized very well (unless they have serious flaws like this carboy), but once the plastic stuff gets any significant amount of bacteria, you should throw it out (or use it to brew sour beers). I say this because it's a pretty safe assumption you got a bunch of plastic stuff off the same guy.
That being said, this kind of wear and tear is NOT normal, and I've never seen or even heard about it. In fact, I imagine I'd probably have thrown it out long before it could get even close to that bad, as it seems for a hole to develop, it's probably far from immaculate in the first place. In fact, it sounds like the equipment must have been SERIOUSLY abused.
I would try to get my money back, but even if that's impossible, I would NOT brew beer with that equipment - anything that touches your beer AFTER it's been boiled can easily infect it, and when you're dealing with used plastic equipment, it's impossible to tell what is and what isn't infected. Especially with the way it's apparently been treated, I wouldn't even take a chance - the beer will in all likelihood be wasted, costing not just the money for the ingredients, but your time and effort. And believe me, it will suck to wait 6-8 weeks only to find out the beer is undrinkable and that making another batch will take another 6-8 weeks!
If you can't return anything, I would throw out all the plastic equipment that touches your beer after it's been boiled (that MIGHT leave you with a spoon if it's just extract equipment lol) and buy new stuff to replace it. I know it really sucks, and obviously you were hoping to save money, but if you take a chance here and brew with it anyways, you will in all likelihood just end up wasting even more money (on ingredients, bottle caps, etc) - as well as all that time and effort I mentioned - only to have to throw it all out two months from now and buy new stuff anyways, which sucks even more, ESPECIALLY when you were just trying to save some money.
On a more positive note though (I think) - welcome to the addiction.