Amanda Bynes is waging war with Twitter and Instagram ... accusing the social media giants of allowing impersonator accounts to claim she's too broke to buy her meds and needs fans to wire her money.
Amanda's attorney, Tamar Arminak, tells TMZ ... she's sent multiple legal letters demanding Twitter shut down "@persianLA27" and Instagram remove "@alb4386" because they impersonate Amanda ... telling fans she's short on money and friends refuse to help her.
The accounts are private but we've obtained a screen shot of a recent IG post claiming she's $63 short from buying meds and begs fans to Venmo her the dough.
The fake Twitter account -- with more than 24k followers -- had numerous replies from fans saying "Amanda" deserves to get money that's owed to her "especially if it's court-ordered."
Tamar says they've been fighting Twitter now for years to remove the account ... Amanda's verified account posted in 2016 telling her followers not to believe the impostors, and then again last year, calling out the fake account for saying she's pregnant and married.
What's more ... Tamar -- who thinks the same person's behind both accounts -- claims Twitter told her the account's a parody and therefore doesn't violate rules. She claims IG told her it doesn't violate their policy and offered no further explanation.
For the record -- Tamar says Amanda's financially well, thriving in fashion school and in a much better place following her 2014 health scare.
We've reached out to Twitter, Instagram and Venmo for comment ... so far no word back.