# Frequently Asked Questions

## Using Duolingo

### Why did my course change?

### What is a streak?

### What are leaderboards and leagues?

### Does Duolingo use any open source libraries?

## Account Management

### How do I change my username or email address?

### How do I find, follow, and block users on Duolingo?

### How do I remove or reset a course?

### I’m having trouble accessing my account.

### How do I delete my account and access my data?

### What to do if your data was compromised

## Subscription & Payments

### What is Super Duolingo and how do I subscribe?

### Family Plan

### How do I cancel my Super Duolingo subscription?

### How do I request a refund?

### How do I use a promo code?

### What is Duolingo Max?

## Still unsure about something?

[Send Feedback](https://en.duolingo.com/help/support-request)