Can a debt collector refuse a payment arrangement? Can they go after the bank account of a co-signor?

Yes, a debt collector does not have to accept any partial payment of past due amounts, they can demand payment in full, or payment arrangements like they want only. ** no truth to that just pay them a few dollars and it is ok**

After they take you to court for a judgement ( co signer is taken to court to) yes they can go after everyone's bank account