recurrent faucet leak: cartridge keeps popping up

Ok, I'm an amateur, please excuse my not knowing all the right terminology.

My sink began leaking a few weeks ago. Not really a LEAK - suddenly the water just started blasting out of the hot side. I shut it off, opened it, put all the parts back in and screwed it in a little tighter - no problem. Then a few days later again - water blasting out. When I tried to set the cartridge in, I notice it wouldn't push down all the way. I decided the seat and spring were the problem, so I replaced the spring and got a smaller one. Still the same. Something seems to be preventing the cartridge from fully setting down in its place, so it keeps popping up. May?be I'm not getting the seat fully pressed down? Maybe the spring is too big? It does seem, upon looking at it, that the seat is not fully 'clamped in' down at the bottom, but I don't know how to get it any further down there - I'm pressing it down as hard as I can. Any advice would be appreciated. -Jamie

 

If would help if you told us what faucet you have.

 

Thanks, and sorry, I'm not at home right now so I don't know the type. It looks very similar to this one:
https://www.plumbingsupply.com/image...02-example.jpg