What legal action can I take against a debt collector for taking money out of my bank account without authorization?

Since I don't know what kind of payment arrangement was made between the creditor and your wife, I can't give you specific advise. I also don't know what the implication may be for you making a payment for your wife, i.e. did this result in the creditor assuming that you would be making the payments for your wife since she had no money in her account.

However, the recordings would be important to prove what the arrangements entailed and whether or not the creditor was authorized to take money from your bank account. You need an attorney to represent your interests, especially since it appears that the creditor is not going to be cooperative. You also need the attorney to obtain the recording so he/she can review it and determine if you have cause to bring a lawsuit against the creditor.