Brakepads are burning tyres out
Get your toolbox, get the 5mm Allen key and align the pads yourself. Make sure they are parallel to the rim and don't touch your tyre when in braking position. 

5 minute job. Saves you tyres and pads.

Update re pictures: Thanks for posting the photos - makes it easier to identify the problem. It seems that your pads are not rubbing the tyres. The problem looks like it's in the pads themselves. These pads are the cheapest possible ones. And they are glazed up. I would just replace them for better ones. Or you can take the wheels off, get some sand paper and sand top layer off the pads. This will work, but it is likely that the pads will do the same again pretty soon. 

Another reason for this appearance - the brake arms are not correctly set up and one of the pads is dragging on the rim all the time, hence "burning sensation". This can be corrected by adjusting the spring: on the side of the brake arm should be a bolt - play with it, until the arms are coming to the rim at the same time.

Or if the brakes stop you well enough and don't drag on tyres/rims, just ignore them and keep riding - not a major problem.