Product: Bank account or service

I went to a chase bank in XXXX, XXXX and wanted to set up a savings account for my mother. She already had a checking account. A XXXX male ( apparently a rookie as he continually had to ask his fellow cubicle neighbor for advise XXXX set it up. I told him I wanted to be the co-owner or signor on it as I have power of attorney and she is elderly and XXXX. The power of attorney is on file with chase and previously approved. There was no problem for several years until I went to the XXXX, XXXX XXXX branch and dealt with XXXX XXXX XXXX, Asst Mgr of the XXXX XXXX branch. 
As background, several things. A. XXXX XXXX on multiple occasions seems to have problems with my family doing business there. B. My mother gets a monthly dividend check of about $ l500 to {$2000.00}. I have deposited these in my mother 's savings accounts without problem in XXXX XXXX, XXXX XXXX and XXXX. XXXX XXXX account states XXXX XXXX and the checking and savings accounts are mailed to her at her mailing address. 
XXXX XXXX XXXX stated I could not deposit these funds into my mother 's account ( savings ) He was disrespectful, almost rude, and seemed to have an attitude with a female teller listening in, that I could not perform this transaction. When I offered to close all of my wife 's, my and my mother 's accounts if he was not reasonable and follow what other branches have doing for a long time, he insisted on denying me this option, without any alternative such as put it in checking, etc. When I took one last exasperating measure for him to look up the deposit history and he would see, that yes, this checks have been deposited into her account for over a year, he relented and granted an exception. 
If he was able to process a transaction, why did n't he do it at the start? 
This is not the first time I have had problems/issues with XXXX XXXX, who does not seem to appreciate customers or their business. In my opinion, a poor example of customer service, and not worthy of promotion due to his style, and demeanor and disrespectful attitude toward me and I assume, how many others? The other tellers and employees including the branch manager have always been great, professional, friendly, and handled transactions in a efficient, quick, professional manner. 
XXXX XXXX XXXX XXXX was also professional, informative and treated me with respect. As a XXXX XXXX XXXX veteran, I appreciate that, and as a XXXX plus member of Washington Mutual and Chase with accounts between my wife, mother and me in the six digits do not appreciate this treatment. 
In closing, I wonder two things. a. Why ca n't I deposit checks or money in anyone 's ( especially my mother 's ) account if I have their account number? ( I am not withdrawing any funds, just depositing them XXXX b. I set this account up for my mother to be the primary and me to be the co-owner and/or POA, if Chase set the account up wrong, how is that my fault? c. If Chace made the error, they should correct it. d. I have already brought XXXX XXXX 's treatment of me to the branch and area manager and they were kind, respectful and explained some or most of his actions. e. The statement comes to my mother and I with both of our names listed on a bundled account, so why ca n't I access both accounts? I have been told, just put a deposit in checking, and I do n't understand why the savings account is unavailable to me. I am not trying to withdraw funds, just deposit them.