Hello Nicky-Elle,
I'd recommend checking the charging port on the case and the actual earbud for corrosion and debris.
-> Clean your Beats Studio Buds and Beats Fit Pro - Apple Support
Information on how to Reset and what the lights mean can be found here:
-> Reset your Beats Fit Pro - Apple Support
If you can confirm these "connections" look good, it's likely you'll need to mail your Beats Pro in for Service.
To be honest, I'd just reach out to online support to setup mailing them in (you can chat with someone with the link below). If you take them to an Apple Store they don't work on Beats in-house and they'll end up mailing them to the same place you would have. So save yourself the time.
Apple Support Contact Methods
-> Call Apple Support 1-800-APL-CARE
For International Numbers or ASL support, click here:
Contact Apple for support and service - Apple Support
-> Chat with Apple Support
Apple Support
-> Get Started Online
Apple Support