Is this the same guy who told you that a humi-bag will last 6 months when used every day as a humidor?

A couple of things... when you buy a cigar in a tube, you can certainly open it to inspect it. If the shop clerk doesn't want you to open it before you buy it, inspect it in front of him after you pay for it. If it looks bad ask him to replace it.

As for the unraveling, are you sure you cut the cap correctly? Cutting the cigar too far down will cause the cigar to unravel every time.