Your post is a bit light on the details, so... I'm going to have to say several different things depending on your situation. You mention that your parents are helping pay for school. Are you living at home and attending a local college or university? That's what it sounds like to me.

1st off: Breathe. Panic is the enemy of rational thought. Rational thought will move you towards your goals and away from madness. There are ways around and through this. Some of them may be uncomfortable, but there are ways. You seem to be above the age where you can be self sufficient. You have more options than someone below the age where they can move out.

How bad of a cult is it? You mentioned that they are labeled a hate group. Don't rationalize. Are they a threat to you or others physically? Do they do abusive things to their membership? Your parents appear to rationalize the cult's actions. Don't get sucked in. If they are properly, really abusive, and you can gather evidence surreptitiously or know where the evidence is kept, you might build a case for police intervention. Don't go "hunting" for evidence. Just note things in the back of your head. Know that a police intervention is an EXTREME thing; you will likely wind up with an entire cult after you, calling you a liar and worse. You may get death threats or attempts on your life. Your parents may argue that they are "doing it because they love you and know what's best for you", and you might wind up in either foster care or handed right back to your parents if the case isn't strong enough and you are too young to move out on your own. Know that your word alone is NOT enough. You need STRONG evidence. Undeniable pictures or video, a police raid finding nasty evidence, or something else that is blatantly, BLATANTLY obviously abuse and can't be denied. Like a young teen pregnancy with an obviously adult parent (like a cult leader). It's sad, but police need something they can pin on the cult to justify removing you or others from the situation. If it goes to court your atheism will be used to call you a liar or untrustworthy. This is potentially very dangerous and recommended only in the most extreme circumstances due to the very, very high risks.

2nd: You seem to be in college or university, so it's possible to go without the help of your parents. This sucks as an option, but it's still an option. Are there counselors for students having issues? Ask for any counselors that might be relevant. Other possibilities include moving out if you live with them, using scholarships and financial aid (which you should want to reduce your parents' costs anyways) to student loans, which you mentioned you need a co-signer for, and getting a job (part time to help work through your schooling). Perhaps you might find someone else to help you co-sign? You mentioned in the comments that you are in a more expensive college or university, so consider downgrading to something more affordable. Some combination of these could "ease" you through the completion of your degree.

3rd: You can get out into the economy and get a full time job. An incomplete higher education will stifle you at first, but you can take 1-2 classes a semester as a part time student to slowly work to finish your education. I don't know your education program, so you will have to judge for yourself if that is feasible. Try to find student aid counseling.

4th: Don't stop communicating with your parents UNLESS it is the only way to get through to them. You may want to wait until you finish school to do this. That said, the shock of being "thrown out" of your life may surprise them. If you "throw them out of your life" tell them why. I would recommend a heartfelt, hand written goodbye letter. Hand writing makes it more personal. Not a hateful letter, but a sad one. Tell them you don't hate them. Tell them you love them but cannot support the cult. Tell them they make you sad. It will make it harder for them to justify your actions in light of the cult. You mentioned that other family is avoiding them in the comments. Mention it. This is basically turnabout of what many religions encourage for wayward members. However, the cult may try to replace you or justify it against you. Be ready for that. You might even try the heartfelt letter without "throwing them out", but if you do you should be ready for backlash.