Fostair short on doses?

[GrizzyWort]

Hi all,I was diagnosed with COPD 4 months ago and prescribed Fostair NEXThaler 100 micrograms at 4 puffs per day as a preventative. For the first month I felt much better and barely used my "blue" reliever inhaler. But for the last few months I've noticed that although my inhaler dose counter reads that it has nearly 30 doses (7 days worth) left, it's actually empty so I start feeling breathless and tired. I'm using it exactly as instructed. For the first 3 weeks I can feel gritty powder in my mouth and for the last week there's nothing. Last month I opened the capsule when it said 30 doses and it was empty, this month it was on 28 left when I felt rough, and again, it's empty. Is anyone else experiencing this? I can't find anything else on line.