MBP 13" speakers broken

You really shouldn't try to fix a MacBook on your own because the hardware can be very hard to find and can be very expensive, sometimes even more expensive than what apple would charge. Apple runs their company like an automotive dealership where they have special tools that only they have, forcing you to come to them when you need help. If it's less than a year old or purchased the additional Apple Care+ when you purchased your MacBook, Apple should cover it if it's a factory defect. I know you did say you reset everything possible but did you reset your SMC? If not, it could be malfunctioning and causing that issue. My brother had that problem before and all we needed to do was reset the SMC. The SMC is responsible for managing the power throughout the system. If you can't find a solution, I would call Apple and see if they can send you a box to you so you can ship it to them.

Are your headphones working? Try plugging them in and out a few times and maybe clean out the headphone port with a wooden toothpick, but be careful. Some dirt in the headphone port could block the speaker sound.

In Utilities, Audio Midi, have you tried configuring speakers?

https://www.ifixit.com/Guide/MacBook+Pro+13-Inch+Unibody+Early+2011+Left+Speaker +Replacement/5151

https://www.ifixit.com/Guide/MacBook+Pro+13-Inch+Retina+Display+Early+2013+Right +Speaker+Replacement/15476