Mixing and Mastering for MP3 File

I am in need of a skilled audio producer to provide mixing and mastering services for an MP3 file. Unfortunately, I have lost the stem files, so the selected freelancer will be tasked with enhancing the existing MP3 file to achieve the best possible sound quality.

Requirements:

Proficient in audio mixing and mastering.
Experience with MP3 file manipulation.
Ability to enhance audio quality without stem files.
Access to professional audio editing software and tools.
Deliverables:

Enhanced MP3 file with improved sound quality.
Final audio file in a high-quality format.

Please include your previous work samples or portfolio showcasing your expertise in audio production. Looking for a freelancer who can deliver quality results within a reasonable timeframe. If you have any questions or need further details, feel free to message me. Thank you!