Whay would you do if your 12year old daughter had 2 D's and 2 F's and constantly is a grouch and has an attitude problem? What should I do?

Her report card grades are as followed:
100A-physical education
75C-Pre algebra
57F-Life science
54F- History
69D- 7th grade honors english
67D- Robotics (required elective also)
85B- Computers

She gives me an attitude constantly and I made her take a nap Thursday afternoon at around 2pm when she was throwing a fit because I wouldn't take her shopping. I work from home and she was on fall break Thursday, friday, and tomorrow. I'm sick of her throwing fits because I won't spoil her. She wants the iPhone 8 but I refuse to get it and I told her I don't care what the cheerleaders have. She will get a job at 16 and she can pay for a phone then. She has a Samsung galaxy s6. I already pay for her braces. She complains about how mean kids at school are to her because I make her wear clothes from target and Wal-Mart. How can I get her to be a good child academic and behavior wise? I took her tv away, I took the iPad away, and now my husband is taking her door away.

Something else is bothering her and she doesn't know how to deal with it; talk to her

See a counsellor and check out that your expectations are realistic - maybe she is doing the best she can.

try and encourage her strengths she appears to have an apptitute for computers be grateful for that and give her some reward for her good marks in this area

I'd get her into some tutoring. But as you seem more concerned with how to pay for her cell phone I suspect that won't happen.

Stripping her of dignity won't help the problem. You'd have an attitude problem too under the same circumstances.

Dayum she is in honors English? You should be proud. Not of her grades, just the fact that she is in honors English. Don't push her and force her to do things. I know she has a lot to do, but if you just shove it in her face, it will seem like a dictatorship to her and she won't do any of it. Just do a little bit at a time. Not all at once because again. It is really horrible. Trust me, I'm 12 and I would know. Another thing is don't take the I pad away unless she has something else to do, and keep the door. What good will taking it do? All I'm saying is that you are treeting her like a baby. Don't spoil her, but give her some control over her grades and how she spends her time. She doesn't want to go to summer school any more than you do. I'm 12 and I know what she is going through.

Retake the class

She's made of fun of at school so of course that would affect her academically. I would talk to her.

It means you failed

What you will need a table, something to strap her down a belt will work, a water pitcher, a rag. OK put her on the table strap her down grab the rag put it over her face grab the water pitcher pour on her face and boom your daughter is shaping up your welcome. By the way i'm joking if the government is wondering

Take her on field trips to the morgue, jails, Skid Row,… So she can see how ne'er-do-wells wind up. Conversely, have her volunteer at fund-raisers, community events and corporate public relations functions to see positive people to emulate. Then get her tutors and counseling. Teach her how to assert herself by assigning books like Pulling Your Own Strings by the late Dr. Wayne Dyer, and testing her understanding of the books.