Stretch Rubber Tie Down 10" Rubber 10 SeaDog Line

I am shocked. These appear to be so s y. I bought these October 24, 2013. I used them to weigh down a tarp that covers a small woodshed. Each tie runs through 1/2 to 3/4 of a broken brick (not a whole brick) that has holes in it, so the weight may be a pound or two, and the tie is then hooked to a corner of the tarp. It is March 27, 2014. I noticed one side of the tarp flapping in the wind. On inspection I saw the tie had broken completely through in one spot and was cracked in another. I checked all to the ties, and all are about cracked through in one or more places. None of the ties were being stretched -- they each just held a small weight, yet they failed within a 6-month period. I know this has been a hard winter, but this is Georgia, not Minnesota. I am VERY disappointed.