How to save other people getting ripped off as well.

So I am sure there are lots of similar issues out there.

Purchased a battery repack for a couple of Shark Shield batteries, cost $380.00. Took a while as I had to post the old battery shells and wait for them to be repacked and returned. Now these gets used for diving and the weather down here does not allow for regular diving. So finally I got out and the units leaked. Contacted the seller and he said send them back. Then it was my fault because my original battery shells had bad valves(!?) Anyway no bad feedback from me as he repacked and returned them. Then I finally get a weather window and go for a dive and the units leak from the valves.

Now the crux, this all took a number of months and way longer than the 60 days.

How do I help other from getting the same experience?

The seller has a 100% positive feedback which is not a true reflection of the quality of his work.

Any way I can get a dispute happening and provide some negative feedback?