How much phone time for a child

How much phone time should a child of the age of 13 have on a daily basis? My husband and I are arguing over this due to our daughter doing nothing but sitting on her PHONE ALL DAY she is Homeschooled and will try to not listen to her classes so she can be on her phone. Missing school assignments because all she does is sit on her phone. She can not do anything without her phone for five minutes. And if you tell her to put it down she gets the biggest attitude and makes you feel like a piece of shit for setting rules for her to actually engage in society and be active/social