Depending on how often you're pumping, the parts on a pump need changing frequently for them to be efficient.
Honestly I think sometimes it’s positioning. Are you exclusively pumping or just pumping between feeds?
I say this because I EBF for the first 12 weeks and only really started pumping recently, if I’m pumping to add to my stash I have to use the stimulation setting a few times to get my letdown going but once it’s going it’s fine I get my usual amount. Sometimes it can take a while but if I’m pumping due to a missed feed it starts straight away
Make sure that the flange holes are all cleaned and not clogged. Also please check the flange size is correct? I use stimulation mode for 2 minutes and then suction mode. Maybe try increasing suction levels?
When this happens with mine I usually take it all apart and put it together again and that normally helps.
I have the elvie pump and have had a few issues as well. I use the triangle (24mm) flange I think? Firstly I was sterilising mine, not realising that the steam was warping the flange so had to order another part and now just sterilise using boiling water. I need to use a really tight bra for it to work properly and even then it’ll only collect around 70ml in half an hour. I also have to wait about 5 minutes to see any milk even though I can feel the let down well before. It’s very frustrating and I would say not worth the cost in my experience x