Barclays Credit Card Complaint

Barclays Credit card department,

APR or interest rate Massachusetts

I bought - computer using barclay card with 0 % APR for 12months. I was paying $100.00 every month. In - 2015 the remaining balance was $200.00 and was charged with - dollars of interest for not paying off entire balance on time. It turns out that it was deferred interest card. Well nobody told me that when I was signed up for card. What kind of practice is that? They made - and lost customer. I will never use barclay services.