Is the connector coming out of the wall too big or too small for the connector on the TV? If too big you should be able to still plug it in it will just be loose, and you can check that your signal is working etc.
This is very strange as coaxial cables have a very standard size, and do not vary. Unless it is a mini coax cable which is very tiny and right off the bat you can tell it wont fit. If that is the case then you need to get a converter.
Otherwise you may be able to use something like this http://www.amazon.com/10pcs-Frequency-Barrel-Connectors-Couplers/dp/B0037JB75S/ref=sr_1_cc_1?s=aps&ie=UTF8&qid=1381528325&sr=1-1-catcorr&keywords=coaxial+barrel
and tape the one end and use a regular cable to your TV. I would first purchase another cable and ensure that it will fit on the TV to ensure the connector on the TV is indeed the right size.