do you have digital caliper? i have measured my original lens (perfect quality!) and the 2-pack of DX replacement lenses, see my post. I dont recommend the DX replacement lenses if you need a perfect beam. I dont think that other boardies ever cared to order the other offerings (see the links in my post).
really sorry to hear. you seem to be the first to report a bad lens in a Romisen! ( i would certainly try to ask DX for some help or for some suggestion. they might ask you to upload a demo video of your light's performance and then simply decide to ship a FREE replacement copy of the full torch or just "a lens" )
my 3 DX samples had all perfect lenses -- that's why i still recommend to get the 3-mode version from them.