Send me an address via PM, and I'll drop a spring in the mail on my way home.
Something to keep in mind is that you generally get better results when you approach things in a mature/professional manner. Making random threats (not physical, obviously) via email, when you're not getting the service you want from another supplier (apparently Summit in this case), doesn't normally get you replacement parts free of charge, from a company that wasn't at fault in the first place.
The GM Model 30304 - Velocity 200 In-Line High Performance Lift Pump description comments under Construction Features:
Compact, lightweight design
Vortex Air Separation Chamber
Pre-set check valve at 8psi
Superior valve design and components for stable pressure
Billet Aluminum Construction with anodize per MIL-A-8625, Type II
High quality mounting brackets that mount directly to frame – no drilling
Long-life, multi-fuel compatible Fluorosilicone static seals
Accepts standard or port style –10AN fittings
Standard canister style filter with water separation feature
Install kits sold separately
The Dodge Model 30303 - Velocity 200 In-Line High Performance Lift Pump description comments under Construction Features:
Compact, lightweight design
Vortex Air Separation Chamber
Pre-set check valve at 18psi
Superior valve design and components for stable pressure
Billet Aluminum Construction with anodize per MIL-A-8625, Type II
High quality mounting brackets that mount directly to frame – no drilling
Long-life, multi-fuel compatible Fluorosilicone static seals
Accepts standard or port style –10AN fittings
Standard canister style filter with water separation feature
Install kits sold separately
Although I agree he should have ordered the correct pump in the first place as it is clearly described on your website which P/N he needed to order, you should have just said sorry you F'd up, and we know nobody has this part listed in their system so we will just send you the correct spring,
Remember to keep good public review, the customer is always right sometimes is the best path to take over a $2 part in a several hundred dollar item! To hide behind the "we only distribute not sell to the public" in this case is horseshit.
People make mistakes, fat fingered the P/N when they typed it in, etc. You have to make allowances for this, not just hang them out to dry.