Pathetic Customer Service - Extremely ANGRY

The Customer service received from H&M is pathetic!! Yesterday, Sunday, 10 June 2018, the Cavendish store did not have the size of the Chino pants that i wanted to exchange for my son, the sale floor lady contacted v&a waterfront store for us, and they advice they have 2 pants left in the size i want. my husband rushes of to v&a, since we need this pants for Eid. My husband goes to the kids section and fetches the right size .The lady that assists my husbands does the exchange, she changes it on the system and issues a new receipt and we leave to go home. Last night i take the pants out the bag , to see it the same pants, we initially took the first time THAT NEEDED to BE exchange, and not the right size my husband when to go fetch, I was furious, we drove around the peninsula for this pants, and to come home with the wrong size again. My husband calls the store this morning, the lady he spoke to gave no apology whatsoever, and said that there is nothing they can do if we want the pants we must come back again. My husband asked if they can send it to canal walk store, he works close-by, for him to collect in the week they said they cant do it if we need it so badly we should come to waterfront to fetch. He then asked if she could please check if they still have the size we want and let him know before 12, so that he can leave during his lunch time to collect, she replies that she cannot promise this it wont happen so quick, CAN YOU BELIEVE THIS????!!! The mistake lies with H&M AND NOT US, yet they cant assist us with a proper apology. I am furious, IT IS NOW 13.45 PM STILL NO REPLY FROM THEM. This will be last time i am supporting this Clothing brand