Red Tape - Return not accepted in warranty period by saying product is physically damaged

I ordered red Tape shoes from Myntra I was happy using them. But after * months of use it's adhesive connecting soul and cushioned cloth got detached. There is gap in there. It's not very big but I have purchased branded shoes that also too costly and facing such type of problem in early period of it's use that made me very upset and when I asked them for return as product was in warranty period they said the product is physically damaged and return cannot be initiated.