i'm adopted and my biological parents want me back but i don't wanna go

What is the reason she abuse? How old are you  now? complaint against your biological mother will not solve issues. better to solve the issues amicably with the support of elders and family member will give good result.

Yes. I agree with the advice of the learned expert Mr.Sankarnarayana  sir.

Once the process of adoption is complete you are de-linked from your biological parents.

What is the basis of forming opinion that the adoption process was incomplete / invalid ?

What is present age and why this issue has erupted at this stage ?

It would be better to consult and engage  a local prudent lawyer for appreciation of facts/ documents, professional advise and necessary proceeding.

Hello, Greetings of the day!
For the query you posted, I would suggest that: 
First, try to settle amicably between the family only, but if in case matters are in the stage where legal action is needed then knock on the door of the court of law.
If you are above eighteen years of age, then you can surely get a restraining order from the court of law against your biological parents. And, you can register a complaint about the abuse against your biological parents. But, in case you are a minor or below eighteen years of age, then the aforesaid advice will be executed by your respective guardians not you. Once Adoption is done, then your biological parent have no right over you.
Also, you have an option to go for the Alternate Dispute Resolution like Mediation where parties in dispute discuss their concern with the assistance of a trained impartial third person who helps them in reaching a settlement.
Hope it helps     
Regards,
Sneha Jaiswal
 

If you are of the age of 18 years or above then you cn take your own decision about this thing or anything which would affect your interest.

Your biological mother cannot force you to return to her home against your willingness even though you were not legally adopted by your adoptive parents. 

You can refuse to give in to her pressures or threats and if the threats are persisting or if you apprehend any danger to your life, you may even lodge a criminal complaint agaisnt your biological mother with the local police and seek protection.