mastectomy bra advice

Hello

I'm looking for help how to find a sports bra that will hold a prothesis after a mastectomy

its over 1 year and still im searching for the above

Im 75 and was given a Nicola Jane & TruLife brochures at the NHS - they don't do them in my size (Im a 34B old bra size) but N Jane were not at all helpful - just wern't really interested to help or point me where I could go.

I wonder if there's someone out there who can advise?

Thank you Susan