Can someone garnish me and my co signer? ?

I have a vehicle that was repossessed and the did the whole auction thing and I owed like $3000 left on the amount that was left. When I got my income tax I paid them $500 to stop legal action. And from there on I've been paying them $109.95 a month as the set arrangement. Well someone stolen my wallet and my debit card's and everything. I advised them of this and advised that I would not be able to pay until the following payday because I literally have no money as it was stolen. I advised them that I would pay the full $109.95 on July 5th when u get paid, they said NO and I must have a payment that is dated for June otherwise they will go after me and my co signer. I guess my question is since they don't want to accept the payment in July and they garnish me, that lady advised that they will garnish 25% of my wages as well as 25% of my co signers wages at the same time. Is that legal? I thought they could only go after the cosigner if I refused to pay, which I never did. I don't mind the 25% of my check but my cosigner too. Something doesn't seem right, I understand I owe and that's not the issue, they are refusing my payment.