Unable to log into MTN app

I have a data bundle from mtn, I use a pocket router supp**** by them. I used to use their App which I downloaded to my phone to check my balances. Recently the app changed and requires an OTP to login. Since my Sim card is in my router I can't retrieve the OTP to login. They told me to use a website to connect to my router to retrieve the OTP, but it doesn't work, so I still can't get my data balance. Something that was so simple now doesn't work... So now I can't gwr my balance and account information.