@Jezza819 TB’s right. I’d like to add that our ear canals are all shaped differently and some people have different depths and widths for both ears.
I would suggest getting some different ear tips if possible. The only frustrating thing is that Bluetooth earbuds are restricted by the case, so it has to be a pair designed by those limits.
You could possibly find a pair of Comply foam ear tips for them; those can be squished then conform to the ear after putting them in. They can pick up earwax, so you have to change them, but they are pretty great.
Comply Foam solves the most common earbud problems — better comfort, better sound, and a more secure, pain-free fit. What's not to love?
www.complyfoam.com