To send this off to someone to fix will cost you at least £80 as the springs and 2 x piston seals are about £45, postage there and back £20, plus labour.This is over half the value of the pistol.Have a go yourself, they are not difficult as long as you mark the position of the pinion gear teeth and rack teeth before stripping.Take off the two screw on pinion caps, mark the positions of the teeth using a small mounted point in a dremel tool.You will need to use one of these as the metal is case hardened.When marked drop out the two little gear wheels, undo the large back cap on the cylinder and release the springs safely as they are under pressure.Pull out the two pistons and replace seals, making sure you use the correct ones for each piston as they are different.Re-assemble fitting new springs if required and compress the back dummy piston until the marked teeth come into line in the round aperture where the little gear goes.Drop back in the little gears you have marked and screw back in the pinion caps. They should screw in easy if the little gears are centralised properly.These pistols are great little performers, just bought back one of the 2 I have owned.
Regards, Baz