SHOE IS TOO LOOSE

I bought Espadrile slip- on Loafers from Sandton City. The shoes are loose, not damaged but there is something wrong with them. I even bought a different colour, same size just to proove my point.

The tan colour SAME SIZE(both size 4) fits perfectly however the light blue is very loose...I am not even confident wearing them.

can i return them even though i bought them last year i think December on account and get maybe another fitting size?

i have worn them less than 5 times because of them being loose