Product: Credit reporting, credit repair services, or other personal consumer reports

My current car loan company has had me at a 45 day deficit since the very beginning of my loan. 
The first payment I brought to the dealership as advised by the dealership. 

At the end of XX/XX/XXXX Santander Consumer reached out and infomed me that my first payment had not been made. I told them that the dealership said they would be making the first payment and when they called me again mid XX/XX/XXXX it was apparent that no payment was going to arrive. At santaders request I went to the dealership because they wanted a written letter saying that they took cashiers check but did not send it into santander as payment. I didnt think that a company would write a letter where they admited theft but I went to dealershop anyway. 

No one seemed to remember waiting on me and they all pointed to the next person. So, I told santander that I wasn't going to be able to get much more out of them but what could i do to fix it. I immidiately made a payment and the salesman on the phone said that if I made another payment asap we could move my due date to the XXXX of the month effectively altering the contract by 15 days and then i would be on time. So i made a payment before XX/XX/XXXX and continued to pay 3 to 4 days before the XXXX of the month cause I was instructed that it would take a couple days and so I didn't want to be late. 

When I checked my credit report XXXX of XXXX Santander Consumer has reported that I have been 30 and 60 days delinquent 8 times in the past 3 years where according to my accounting i've only ever been 17 days late and in that case I ended up making a double payment as my next payment and then without missing a amonth continued paying normally. 

It took about 5 months of calling and trying to figure out where these delinquecies came from when I just got this information from a rep yesterday. I have been 45 days late always. They never moved my due date nor did they change anything at the begninng of the loan so my XXXX and early XX/XX/XXXX payments didn't seem to catch me up at all and because I was paying at the XXXX of the month I was 30days late plus 15 days because my actual due date is the XXXX of every month. 

This is information I was never told and after speaking with the company so very often i am confused as to why no one mentioned that i was paying every month at the wrong time and or that i was already 45 days late from the get go. So XXXX and XX/XX/XXXX payment counted for XX/XX/XXXX and XX/XX/XXXX so my next payment in XX/XX/XXXX meant that XX/XX/XXXX was the last time i paid technically because that's what they never honored their own suggested plan of action to get current. Nor was i informed that i was not current. Operating as if I was paying on time at the right time you can see that throughout the last 3 years my payments are steady and adhere to the assumed due date only going 17 days late once, which they recorded as 72 days late. 

It took me 5 months for everyone to figure out why anything was considered delinquent, I believe that this is a total abuse of power and cost of loan and interest and delinquency is a required piece of information to report not just to the credit bureau but also to the consumer. 
Over the course of 30 months never once did they question my payment schedule or comment on my always 45 day deliquency. I did however speak to someone at the company at least once every 2 months and in XXXX of XXXX even spoke with someone about the change of my intinal due date because of the theft of the first payment to which no counter information was given at that time, no information I said was refuted and I took that as a verification that I was paying on time and on the correct date. 

They claim that they are reporting correectly and that i was delinquent and that is the end of the convo.