Woodland — Shoes colour changes

As i purchase men shoe gc2567117rt, o green 40, on 14/06/2021 bill no. 202102N1500C00192 now thier colour changes as one becomes dark and anotherone becomes light, i visted to showroom as they suggested me to polich them but my query is that in one month this is happening y shoud i polich them u need to satisfy the customer once that it will be ok after policing. if i did policing if not then replace it if not gone right u will blame me, so kindly do the needful rply me with satisfactory answer