Bad customer service

I AM not happy with the way I was treated by this Company, they did not send me the statement, or an SMS to tell me how much I was supposed to pay at the end of December, and you just send a threatening SMS saying this is the final reminder, what kind of service is this, I did not get any 1 sms to tell me the installment, I think I made a mistake by opening an account again with this Company in November , they have not improved on anything, This is not the way to treat your customers, I would never use this account I would just pay off and close it again as I did before