Sources close to Amanda Bynes tell TMZ her friends are fuming mad with her family ... wondering why they aren't doing more to help the troubled actress before something REALLY bad happens to her.

According to our sources, Amanda's friends do not understand why her family is not being more aggressive when it comes to her wellbeing. We're told her friends are perplexed why they are just standing by and watching Amanda self-destruct.

Our sources say her friends (who feel they have done all they can) want her family to literally break down her door and drag her to get to help.

But that's a problem ... because we're told Amanda has slowly cut off communication from her entire family -- dad, mom, sister and brother -- to the point where she has ceased all communication entirely. 

As TMZ first reported, Amanda's family recently moved from Texas to California to be closer to her. According to our sources, they are having the same level of success helping her now as they did before.

NONE.