Problems w/ Corsets

I won a lovely corset from EBAY.....and had problems from the get-go. When I tried it on, one of the button pins just popped right out of the front. I told the vendor & they sent me a 2nd corset, and I sent them the 1st one back on Friday. I wore the second one to Baycon, and after wearing it a few hours, I noticed it was starting to tear along 1 of the seams in the front. A friend of mine was wearing the exact same corset, and her's was tearing too....in the same place. I sent the vendor email when I got home....mostly as an FYI. She's offering to send me a third corset now. Should I bother, or just cut my losses? Btw - the vendor was subtly indicating the tearing was my fault because I laced the corset too tightly. According to her, when you wear leather corsets, you should tighten the laces gently over successive wearings....to give the leather time to gently stretch & conform to your shape. Funny thing is....I wore a different leather corset that same weekend, and had no problems at all with that one.