I had some nice big oxygen and acetylene tanks given to me, had a neck band for a local distributor (not customer owned).
Called a different distributor that I do deal with and they said they couldn't fill them or exchange them (as I expected). Also said if I took them to the supplier that they belonged to to have them filled they'd want to see papers showing I owned or leased them, which I didn't have, and they'd probably keep the tanks. So the only way for me to use them would be to buy/rent two more tanks from that same supplier and I'd have myself a spare set they wouldn't know about.
In the end I gave them to someone else who already had an account with that company... because when I get some tanks it'll be with the other company that I do like dealing with.
Grigg