Discover Credit Card Complaint

Discover Credit card department,

APR or interest rate Connecticut

Hello, I am using Discover credit card and I pay off my monthly due on time with full due payment as per their statement to avoid interest. I also used Discover promotions like balance transfer with 0 % rate for next 18 months with initial fee. Let us say by using that promotion, if I transfer $3000.00 on -/-/- and they charge me $90.00 on the day of transfer initially and then I have to pay off that amount on or before -/-/- So my understanding is that from -/-/- onwards, if I pay off my monthly purchase transaction as per monthly due, I wo n't see any interest. because my balance transfer loan is 0 % for 18 months. But every time I pay off my monthly due as per their monthly statement, they still charge me some interest. I asked them why then they mentioned, I have balance transfer loan. But that is 0 % for 18 months. As a consume, I am not able to understand their explanation. I can provide my last 24 months statement, you can look at it and see why those interest charges applied every month. They are charging me initially 3 % of loan to provide 0 % for 18 months and then they are charging interest fee every month. But I am paying off my all monthly purchase transactions as per their statement. Let me know if my statement make sense or not. Thanks