Hmm, doesn't sound good that. I'd expect a refund / replacement as the kit is obviously not up to the job. Even a cheap suit in my opinion should be resilient enough to take a moderate amount of caving, otherwise what a pain in the arse!
My Warmbac suit has been caving in Derbyshire on average twice and somtimes 3 times a week for the past 12 months, and done a lot of digging, and is still going strong. A couple of holes have worn in at the rub points, and the cordura is obviously getting a touch thin, but it's still going well.
I wouldn't want the hassle of a: having to return a suit to a shop, whether I posted or delivered it and b: having to go without a suit while they fix it!
Get a refund, if you can.....