If you cannot get the pool liner to fit, you should first search & read:
I have installed the pool liner and it does not look the way I would like it to, what do I do? 
Also read one of these (depending on whether you have an overlap or beaded liner):
How do you change an Overlap liner for an above ground swimming pool?
How do you change a Beaded liner for an above ground swimming pool?
 
If you are having problems after trying to install a liner: ninety nine times out of a hundred, the swimming pool liner needs to be readjusted, or reinstalled. It almost always points to imperfection on the installer's end. No big deal, but your job is not complete. It is much easier to pump the pool out again, readjust, or to fix and reinstall, by restretching, than to warranty a pool liner, pay for the shipping expense, and wait for it to come.
If the liner that you received measures to be within 2-3 feet of the size ordered, then you have the correct one and are just a little timid stretching it in. They are all made short of the dimensions. They are all intended to stretch into place.
Too help you get a little gutsy with the stretching process: here is one way that I like to explain it: "If you held a pool liner out like a plastic bag and filled it with water, it has the resiliency to triple in size. That's why they make them smaller than the actual dimensions....so that you must stretch it into place."
If you find yourself in this predicament here is a good tip for restretching and adjusting: pump the water out, redu the installation, and place the hose of your shop vac in the skimmer box hole. Duct tape the openings of the square as well as the return hole, turn the vac on, and watch the liner stretch like magic. Only do this service, as well as any water filling in 80 degree plus weather.
As a professional it took me dozens of liner replacements until I had the confidence to stretch a liner without anxiety.
Remember, you are the one acting as the service technician, and if you do not learn some of the tricks, then you are going to end up paying for another liner, so either lose your timidness and redu the job. Or you can pay the price of a plane ticket and $500-$1000 for service and we will send someone to do it for you. You can do it!!! Good Luck!!!!!