Myntra.com — offer lapse by company

Address:

Bangalore, Karnataka

Order#[protected]-6533303 i ordered 5 items in this order with total amount of rs. 3109, i purchased these items on july 28, 2018 in clearance sale with offer of citi bank credit card (15% cb on order above 3000).
But suddenly i came to know one item in my order which is a t-shirt which i purchased xl size and it was last product and then product was showing out of stock. Price of this product was 187 rs.
When i contacted with customer care they told me that they have cancelled it by their own t&c and not even sms or notified me and the reason was very pathetic (Product issue) this cancellation makes my order amount