Complaint sub-issue: Having problems with customer service

On XXXX XXXX, 2016 I spoke to Supervisor XXXX XXXX regarding my account. This is a summary of the undisputed facts. 

On XXXX 2016 I finished my XXXX and moved on to Florida for my XXXX. I submitted adequate documentation to all the different banks from which I have loans and requested a fellowship deferment. It was granted by all of them except by SalliMae. Unfortunately, I was no notify about it. 
On XXXX, I started to received automatized phone calls regarding a debt with Sallie Mae. 
I contacted SallieMae to inquire about this. I was told that they did not receive my deferment application. I confirmed the previous fax number and it was correct. I re-faxed the document and sent a mail copy. Two weeks later I continued to receive phone call from SallieMae, I contact SallieMae and I was told that my documents were being process and that it was an automatized system and they had no control to stop it. 
One week later the automatized phone calls became harassment about 10 a day. I called SallieMae one more time and was told once again that my documents were not there yet. I told them that this was impossible that I already confirmed with them that they received it. The person who answer the phone at SallieMae confirmed me that everything that we talked was documented but that for some unexplainable reason the document was no there. This time I was provided with a website in which I could upload the deferment form. I de-authorize SallieMae from contacting me by telephone. 
Once again, I contacted SallieMae during that week to confirm that the document arrived. I was told that everything was in order, that I do qualify and that it was a matter of processing. 
On XXXX, I received a phone call from an account manager XXXX to call back SallieMae regarding a balance in my account. This was surprise for me. 
I called the same day to the telephone number she provided and another employee talked to me. This person was very unprofessional and at some point I felt threaten by him. I tried to explain the situation and asked him to revise my file. He interrupted me and told me that the system indicated that I graduated. That I needed to pay over a thousand dollar immediately. That he already had raised a flag in my credit score and that he will continue to do so the XXXX of every month until I pay the money. Then he told me that the deferment period is only for 36 months and that I already use that period. 
The next day ( XX/XX/2016 ) I called my SallieMae account manager XXXX. She verified my record, confirmed that everything I told her was true and she apologized for the inconvenience. She told me that the documents were received in XXXX but were not submitted for processing. I asked to talked to a manager. She transferred me to XXXX XXXX. He went over my account and previous encounters. He also confirmed that EVERYTHING I said was correct. XXXX XXXX apologized as well and told me that he will make sure that the processing was adequate at this time. He also told me that in effect SallieMae had submitted my name to the Credit Bureau but that he personally will submit a Credit Rectification document. I told him that I understand that mistakes happen but this process have been very abusive to me and that at the moment it was difficult for me to trust SallieMae. I asked him for written evidence of their acknowledgement and that I wanted the specifics about the credit flag that they raised in my name. He told me that the only way I could have access to that information was through a legal process. Then he implied that if I decide to go through the legal means the process will be slower than using a credit rectification form. XXXX XXXX told me that I will receive a call on XXXX XXXX to confirm the submission of all documents. 
On Friday, XXXX XXXX I did not receive a call form SallieMae. I