Questions about Airtouch f30i and DME

About 5 weeks ago, I went to my DME (Prism Health) for a fitting. I requested to try the resmed Airtouch f30i and airfit x30i. I had been using the f40 for a few months, and was looking for something to improve my leak numbers and comfort. I went home with the f30i, and have loved it. My leakage is down, and it's very comfortable(no more sore septum-yay!). After 30 days, it's time to replace my cushion, but my DME tells me that they do not have the cushion, can't tell me when they can get a cushion, and offer me no alternatives other than to call resmed and complain. I received an email telling me "the mask has not officially launched to the public or Provider's(sic)." The mask and parts are available all over the internet, even 4m4z0n, so I think they're lying. I have asked them to contact their dedicated sales rep to see if one can be sourced, and will probably order one online from out of pocket. Should I escalate my issue? Is changing DME difficult? Are there any that are recommended? I have regular Medicare with a part G supplement. TIA.