Defective CPAP Filters

I am very concerned about defective CPAP filters. I receive generic filters for my ResMed CPAP machines from my current DME. They are defective due to loose fibers and not fitting snugly to the filter tray on the filter door. They do not discolor after a month of use as do OEM ResMed filters I've used in the past. I have used them for a year before realizing by close inspection they have exposed fibers that easily come loose. They are difficult to install due to being a bit smaller than the tray in the filter door. Without a snug fit, they move as the door is closed.

Looking at a big online sales site I see there are several manufacturers of filters other than the ResMed brand that are up to 90% less in cost. They have no specifications for filtration effectiveness. I am suspicious they are not made to any proper standard.

I have appealed to my DME to send me ResMed filters, not the generic ones I have been shipped. I am waiting for an answer.

Has anyone here had a similar experience with defective filters?

Thanks.

My wife and I both use a CPAP but have no insurance. We have bought our own machines and pay for any parts or accessories we use. Some time ago I got a package of 60 filters from Amazon for about $17. In comparison to the OEM ResMed filters I find these filters to be better quality. They are much finer and fit well in our A10 machines. I replace them every 4 months, so it will be quite a while before I have to order more. I do not consider them as defective, but actually superior to the ResMed filter. As far as I know the ResMed filters have no specifications either. But, they are obviously much courser in texture, and probably last longer before they start to plug up as they don't catch as much dust. I judge how effective the filter is by how much dust collects on the outside of the filter and how thick that coating is by 4 months. For these filters and our house dust conditions, 4 months seems about right.