I have had a close look at
Campanula argyrotricha. if you look at the description and drawing at FoP
Plants up to 20 cm tall, stems numerous,
procumbent, thread-like, pubescent. Leaves oval to ovate, up to 1 cm
long, 5 mm broad, margin toothed to wavy, surfaces white pubescent.
Pedicel c. 0.5 mm long. Calyx teeth about half the length of the
corolla. Corolla blue, hairy outside; style exserted. Capsule rounded at
the base.
The highlighted features don't agree with Prashant's flowers. In Prashant's flowers the sepals are smaller, and the style is not protruding out. In Campanula argyrotricha the sepals are indeed half as long as the flowers, as can be seen in the attached herbarium images (from GBIF).
I have also attached the drawing of Campanula cashmeriana from FoP and a herbarium image from GBIF. Looking at these it appears that many images of Campanula cashmeriana that appear in Google search may not be correct. Prashant's flowers do appear to agree with the sketch of Campanula cashmeriana at FoP.
Best wishes
Tabish