Rcs payment in advance but put a bad mark on my credit score and nothing can be done about it

I have never missed payments in my life..they directly affected my credit score by saying I did not pay account.i paid in an extra amount of 1500 in the middle of a month so I didn't have to pay at the end of that month because i was on holiday..they say that payment makes no difference if it's triple the amount I was supposed to pay as it needed to be paid only end of the month not earlier..so because I paid 3 times what was due..but it was paid in advance..it does not go for end of that month payment..I needed to pay 400 and I paid 1500 before the 400 was due so it goes as non payment..make that make sense..I will be closing my rcs and never using it ever in my life again..upset and disappointed that even calling to try and fix things made no difference. I feel like I have been ******. Unacceptable and dissaointing