Garanti BBVA Charged Me Unfair Interest After I Closed My Advance Account

I really don’t understand Garanti BBVA. I closed my advance account, paid the outstanding balance with interest, and thought everything was settled. Now, after about a month and a half, they’re telling me that my account remained open and additional interest accrued. This is completely unfair. On top of that, they’re asking me to visit a branch to sort it out. As someone with a full-time job, how do they expect me to take time off just to fix their mistake? I’m a salaried customer, yet instead of providing a proper solution, they’re making things unnecessarily complicated. If this issue isn’t resolved fairly, I’ll have to consider switching banks. I expected better service, but this has made me reconsider my trust in them.