I would assume instead that the razor they sent you was not shaving sharp. This happens A LOT more than you'd think, even with some products from Solingen manufacture. Resting the razor sideways on a towel, not wiping off oil or having a beard (even a full beard) are no showstoppers for a perfect shave. You can't shave long hair with a system razor, but straight razors do it without a hiccup. I wouldn't worry; you most likely didn't ruin the edge. It simply came dull.
Yes, bad technique will dull the blade a bit faster than good technique, but ultimately every shave will put wear on it. You need 3 things here: Leather strop to straighten the edge before every shave (not afterwards, let the edge rest for at least 1-2 days after a shave), another strop with some very fine polishing paste (I use an old leather belt with chromium oxide paste) that you'll use ONCE when blade sharpness cannot be restored to satisfaction by a simple strop anymore, and finally a very fine stone to sharpen it on, if you ever **** your blade up. 6000 Japanese grit and upwards, this is basically the coarsest you'll ever use on a straight razor.
I haven't had my straight razor that long yet, but I can get 10-15 good shaves and strops out of it before I have to paste polish it once. But the number can be as low as 8 or as high as.. dozens. Some people think paste is a travesty, but they usually have various sharpening stones to make up for it. Stropping technique is also very important, you can ruin an edge with too much pressure.
The proper way to strop is to hold onto the metal bit below the blade with index finger and thumb on the sides (no hard pressure from the top!). Lay it flat on its side against the leather so that the spine as well as the edge equally and lightly touch the leather. Then drag it slowly (speed comes when you've got the technique down) in the direction of the spine. You'll hear a distinct, light sound telling you that the edge is being stroked. Most strops are not wide enough to accomodate a full blade, so you'll strop slightly diagonally to make sure the full edge is being stropped. When done with a stroke, turn it around 180° with the blade turning upwards and repeat the stroke in the other direction. You don't have to pull too hard on the strop, just lean back a bit and let your bodyweight keep it straight. The big thing is to find out how light of a touch is light enough so you work the blade without doing harm to it. I usually do about 20 strokes for each side, but YMMV. Still learning all this myself.