Subcontractor Agreements Changes, unfair?

[Guest]

Hi, I have been working as a translator/proofreader for a translation agency for 7 months. They asked me today to sign an updated Terms and Conditions agreement. I have refused to sign it and explained in a 3-page document that it is because one of its clauses is that if a poor translation is done, the translator should take on the entire financial responsibility, reimbursing the company for the lost payment and retranslation fees if the client refuses to pay. I earn about 20% or less of the money they receive for a translation (the company has extremely high profit margins), so having to play >100% would kill me for a month. Small errors can lead to a client refusing to pay and they can be caused just by human error. That is why with all professional translation, there absolutely must be a review by someone who didn't translate it, according to European translation standards. The company guarantees on their website that translations are proofread and revised twice after translations. I have evidence that this does not happen. Now I worry that refusing to sign it will lead to termination of working with them. Was it fair for me to refuse to sign this new contract? Is there anything I can do to stop them replacing me? I also worry for the other thousands of freelance translators in this company who may sign their bank account away with this agreement.