So I know this might be weird but I don’t know why my bra doesn’t fit right I think I need a 36-B or 38B but that hard to find I have a wide back but my boobs are on the small side I went to VS and the girl was no help I got a 34-B and I have an extender at home but even my new bra doesn’t fit right

My problem is it keeps riding up all of them old or new my boobs fall out from under and I have to keep pulling it down. It’s super annoying if anyone could help that would be great.