I refinanced my home mortgage through JP Morgan Chase and my first papment was due XX/XX/2016. I made my XX/XX/XXXX and XX/XX/XXXX payments at the teller windows at XXXX different Chase branches. These payments were made with checks written from my credit union checking account. I made my second payment on XX/XX/XXXX and a few days later I saw that my credit union balance had more money than it should. I then looked at my receipt from my XX/XX/XXXX mortgage payment and it showed that my check had only been deposited for {$1000.00} instead of the {$1600.00} that I 'd written the check for, which is slightly more than my mortgage. The next day, which was Friday, XX/XX/XXXX, I contacted my credit union to see how much the check had been deposited for and they confirmed that it had been deposited for {$1000.00} dollars, but I had written the check for {$1600.00}. While talking to customer service for my credit union, I mention that I should probably write another check to Chase to cover the shortage. The person from customer service told me to hold off writing an additional check and that she would have someone from accounting contact me. That same day, a lady from accounting said that she had " pushed through '' the addition {$600.00} to Chase, because that is the amount the check had been written for. I then contacted Chase customer service to let them know about their mistake and that the shortage was being taken care of by my credit union. Chase customer service transferred me to the branch that took my mortgage papyement and I spoke to, XXXX, the teller that actually made the mistake. I explained to XXXX what had happened and that the credit union was pushing the additional funds through. XXXX suggested that I write an addition {$600.00} check by to make up for the shortage and mentioned that this would ensure that I would n't incur any late fees, or that my credit score might be adversely affected if the payment was late. I then called accounting for my credit union and was told that the additional funds were enroute to Chase and that I should not write them an additional check. I was also told that the only way that my credit would be affected by Chase 's mistake, was if Chase reported it. The lady that I was speaking to in accounting gave me her name and direct phone number and said that it would be fine to have XXXX from Chase call her. I was told that it would take approximately XXXX days for the funds to reach Chase. The following Monday I confirmed that {$600.00} had been withdrawn from my checking account. Later that evening, I received a phone call that I was n't by able to answer. Later, when I called this number back, I learned that it was Chase. I spoke to customer service who had tried to call me about my past due payment and that I was now being assessed a {$65.00} late fee. I spoke to customer service and explained what had happened. I was told that the late charge would be waived, I would receive no more calls from collection and that I would be contacted in seven days if the additional {$600.00} had not reached Chase. I was told that all of these promises would be documented in the notes for my account. On Wednesday, XX/XX/XXXX, I received a phone call from collections. I called the number back and XXXX asked if I planned on keeping my home. I told her yes and asked her what the notes said on my account. XXXX said that there were no notes in my account and no record that I spoke to customer service on Monday. I explained what had occurred and that it was Chase 's mistake that had caused this problem. It was quite apparent that XXXX could care less about my situation. I demanded that she pull up a copy of my check that I had used to make my mortgage payment, which XXXX confirmed had been written for {$1600.00}. My account is still showing that I owe a let fee.