92301 air filters must be purchased through PM

[Peter Sik]

I have a rental property in area of 92301. I tried to Amazon my tenant air filter 3 times a year. My PM said " the air filters must be purchased through us by the owner or the tenant due to Fair Housing laws." I never heard something like that and couldn't find any information regarding the AC air filter must be purchased through PM. Does anybody know about this is true? PM is charging me $10 monthly for the air filter subscription service.