corolla fog lights

i have a corolla 2003 TRD model and last month i bought a pair of aftermarket fog lights for it. i went to several bodyshops and they told that they could'nt be installed because the lights dosnt fit very well. can somebody tell me why the lights didn't fit? where can i buy fog lights for my corolla '03? If a corolla S owner is interested in selling their fo lights to me i'd be glad to buy them.. thank you!!