I began leasing oxy/acetylene tanks from Praxair in 1988 when I was barely a teenager. Couldn't afford a mig, so everything was gas welded or brazed, or cut with a torch. When i got my mig in 92, I leased another bottle for 80/20. All my bottles were around the 120 cu/ft size. Around 2002, the manager of our local Praxair called me and said my lease was going up, and maybe i should buy out my leases. It was around 450 a year for the lease by that point, and about $1200 to buy all my tanks. Done deal. I paid, and everything was fine for almost 20 years. Exchanged my tanks fairly regularly and never had an issue. One day i go in, and no familiar faces. My account also could not be found. They exchanged my mig bottle and oxy, no problem but said it would be the last time. Next time i go in, they tell me sorry, you can't own a 120 cu/ft tank, those are leases. Somewhere along the line they changed the rules, but it is still not resolved. The manager wouldn't even talk to me.
Thankfully my bud owns a big welding company, with a big account there, and now everything works. They won't even exchange my 120 ft bottles for 80's.