<human>: In July of 2012, my wife had a pregnancy-related $700 test performed and the insurance was filed incorrectly (must be mailed in, not processed electronically). We had repeatedly told them of the procedure for filing to the point that my wife made notes of how many times we had to correct their information because it was input incorrectly. We were never contacted regarding their trouble in processing so we figured they finally got everything taken care of.

Fast forward to today, my wife receives a call from the hospital requesting payment for a past-due bill for the full amount of the test... $700. Last month, my wife's insurance lapsed and she enrolled into a different plan with a different company, so even if they were to follow the correct filing procedures for the previous plan, it wouldn't go through since the claim is being filed after the plan became inactive. 

We are unsure of what to do and have been arguing with the billing manager for the past hour. We don't feel that we should have to pay the whole bill since it was their fault for not processing the insurance correctly the first time, even after being told specifically how to do it.

Can you summarize the given text in a few sentences?
<bot>: Hospital billed insurance incorrectly over a year ago on a plan that has since expired. Now they are demanding payment for full amount or send us to collections for their mistake.