I know Facebook has seemed to have issues in the past 3-5 months but not sure you can call it iOS 14 issues yet. Apple hasn’t launched the new opt in prompt yet (and doesn’t have a specific date set at this point) so it’s likely more seasonal issues. I have no idea what sector your clients are in but after Q4 retail season wrapping up there is always a lull afterwards. I’d compare to previous years data to see how significant the changes are YoY before you look into anything else. Check outside the platform tools too. Don’t rely on Ad platforms as the source of truth if you can help it. Hard to say it but if a client talks to you that way, they likely don’t respect your work/expertise so might be good to part ways with them. Someone who doesn’t respect your work is not likely going to be a good reference for new business anyways as it sounds like they treat you like people doing the work and them driving strategy