Compounding pharmacy recommendation?

It seems that some batches of my son’s compounded medication work and some don’t. (I’d rather not give specifics, but the difference between the medication “working” and “not working” is not subtle) 

My compounding pharmacy in Walnut Creek says a faulty batch is not possible, but when they send a replacement batch (“as a courtesy”), it always works. We’ve been through this routine three times in the past year. 

Anyone have any insight why this could be happening? (E.g. incorrect storage/mixing/measuring?) 

And are there any stellar, reliable, compounding pharmacies in the east bay? 

Thanks in advance for your knowledge and recommendations.