That bites! Did the seller represent the larger sails as fitting the H14, or did he just throw them in with the deal?. If the former, he should take 'em back/reimburse you. If nothing else, I'd voice my extreme displeasure (like a sailor!).
Any insignia, manufacturer info, etc. on the sails? Pix might help identify.
Sounds like you really need help from someone with more Hobie experience. Contact your nearest Hobie fleet:
http://hcana.hobieclass.com/hobie-fleets/ Even if they aren't real close to you, they may know someone who is.
You say that the jib is too big....did you step the mast and otherwise set up the boat to determine this? If so, how did the mast connect to the bridle? Trying to determine if you purchased a "regular" H14 or a H14 Turbo. The stock H14 does not carry a jib, so it should have a simple forestay/bridle arrangement, and it should not have a swivel (above sail), furler (below sail), dolphin striker, or jib cleats on the tramp. The H14 Turbo should have all four of these plus a roller furling jib with a wire in the luff that acts as the forestay.
I have an old set of sails for the H14 Turbo. They are so worn that they'll probably explode in much wind at all. The main fits both the regular and Turbo models. The jib is only useful if you have a Turbo, and, even if the sail explodes, its luff wire is still useful to hold the mast up (to sail the boat under main only). Once you figure out what you do and don't have, if you really want these old sails, send me a PM.