Scooter Wheel Making A Sound What Can Be Making The Noise On The Rear Wheel Of My 50cc Cool Sport Scooter?

What can be making the noise on the rear wheel of my 50cc Cool Sport Scooter? - scooter wheel making a sound

I heard a knocking or scraping noise like metal sounds like it comes somewhere in the rear, while I drive on the street. A few weeks ago, the rear wheel brake of the leak out of place and somehow new brake pads put on it. Sounds like maybe it could be something wrong with the brake pads? This bike is only 2 months, but was guaranteed for 1 month. I have had nothing but trouble with this thing starts on the day I bought it and I wanted another bike, but left me no other. Instead, the owner was just stupid and apologized for the insult to me .... trying to make my own mistakes. One day I went up to him and told him what he thought of his bicycle. I am a woman of 58 years due to a disability retirement and my only transportation right now. I desperately need help and need to learn to work on yourself ... if possible. Besides, you know where I can find a total length of the auto repair ... Explanations for this bike?
Thank you!
Kathleen