Help! need to find a new base ring.

Hey all we bought a metal device as our first one.
it's fine for short term use (an hour here an hour there).
yesterday i was ordered to wear it for 24 hours i made it but it hurt like hell a few times, and when i took it off i had a red ring in the skin where the base ring had been.

i have seen new rings available somewhere but i just can't find them now.
the one we have is only 40mm
have attached a photo of the ring.

any help is much muchly appreciated.

 

there is the problem. by time time the exchange rate and shipping is taken into account cheap from ebay doesn't stay cheap.

 

Pound to NZ$ is about tripple. so cheap doesn't remain cheap like a said.
i think i might hust have to fabricate one.