I believe the cups are too close together and/or too narrow. I also think the band is too big (see
28C - Freya » Deco Moulded Soft Cup Bra (4231)
Pink 28C - gaps at the top? band too tight : r/ABraThatFits
7 Common Bra Fit Issues & How to Solve Them - Solutions to Common Bra Fit Issues
7 Common Bra Fit Issues & How to Solve Them - Solutions to Common Bra Fit Issues
28C Black Bralette, Bra for Small Breasts, Supportive Bralette, Yoga Bra, Wireless Bra, Petite Bra, Convertible Bralette, Cross Back Bra
Choose the correct bra cup size when changing band size
80% of Women Are Wearing the Wrong Bra—Here's How to Find Your Correct Size
Bra Fitting: Guide to Fitting the Right Bra for You
The Corsetiere - Signs that you're wearing a badly fitting bra: 💕 Bra cups are too small and the bands too big 💕 Telltale signs of a band that's too big is
How I Gained A Cup Size Overnight, by Marissa Hastings, Your Breast Self
Is it normal for your bra cups to be too small but your band is too big? Like my size right now is a 36A, but the cups are too small but
What is my bra size? My underbust is 28 inches and bust is 32 inches. I was previously recommended a 28D, but the band was too tight, so it didn't fit. - Quora
How to measure Bra Size, Bra Fitting Tips
Is it normal for your bra cups to be too small but your band is too big? Like my size right now is a 36A, but the cups are too small but
28B - The Little Bra Company » Nicole (F005)