No response to customer emails , unresponsive portal

I sent a mail to the customer service email which the company stated that customers can use at any time and of which a customer agent provided it to me while on the phone , the email was sent on 4 January 2018 for them to update my banking details today it’s 15 January my email was not attaended to and my banking details where not updated, I wanted to do it myself since no one cared to attend my mail, the portal asked me to request an OTP which it did not generate , bad service