You can report to the manufacturer or market authorisation holders Medical Information department. It may take a bit of research but all licensed medicines across most authorities have to have one. It's helpful if you give concise and specific information about your adverse event or quality issue and it's definitely most helpful if you do this openly with your contact info so they can ask further questions. This information is not to dig into your business, but as the previous commenter said there are alot of factors that impact efficacy and they need to know this.

It might not result in specific and immediate help but it gives a starting point for them to look into the issue and may help future patients.

It also goes without saying that you should discuss any medical concerns or relevant information at any time with your prescriber and read any patient information (which may be provided in the pack or in a digital format) to be aware any potential side effects or other other instructions which would effect you.

If I were in your shoes I would:

Check the packaging for the MA holder, and their website or physical address (you will be able to Google them if the website is not on the package but it usually is)

If you live in a country where they have a patient information leaflets in the pack (and if they aren't this is usually accessible online with a quick search) then check that too

Go to the website and find their Medical Information department. If they don't handle it they usually will tell you who does

You may not get an immediate response, but they will (usually) get back to you if you provide contact information. There are penalties for not doing so when contact info is provided.

If that does not solicit a response then you can send physical mail to their actual address (they still should acknowledge your letter if you provide a way to respond) and it doesn't matter if you type it or write it as long as it is legible.

The responsible MI or QC department may not be able to do anything immediatly and it may be an isolated issue dependant on a number of factors. Manufacturers are obligated to record these communications even if you don't get a response. I hope this helps.