gaz coilover rebuild cost

[lolsteve]

So I think the rears coilovers are a bit shagged. They were bouncy as balls when first fitting as if there was no damping which doesn't match up with the sellers "7 clicks from hardest"
Also in an effect to loosen one of the damping adjustment dials I might have broke the valve inside as the adjustment dial spins in either direction forever now when using a bit of mechanical aid, the other shock is too stiff to adjust by hand so will be trying a bit of penetrating fluid to try and loosen it.

So will no doubt be having to send them off to Gaz for a rebuild, any idea on the cost?
Also these were apparently serviced 2 years ago by not the previous owner but the guy before him who after having it done put them in a shed for a bit before the "seller" bought them put them on the car and left it behind when going to uni

Just a bit distraught now as I tried to fix the problem of bouncy suspension and all ive done is fk it all up and everything is starting to rattle from no doubt being bounced about all week with not having damping