Myntra - Myntra selling products of companies which seemingly are fake

I ordered a Tommy Hilfiger tshirt on **th May **** and received it on **th May ****. As it was XL size printed on the t-shirt which is the size i ordered i straight away cut the tags and washed it as a precaution from covid and did not feel the need to try it trusting Myntra will not deliver a duplicate product.
However to my surprise when i tried in the evening of **th may it was way bigger then printed XL size. I called up Myntra and told them about the manufacturing defect that the size printed on the t-shirt is wrong and kindly take it up with Tommy Hilfiger company for this misprint of size.
Myntra straight away refused and said they don't have such policy.
Now my question is why Myntra is shying away to take it up this manufacturing defect with Tommy Hilfiger company? What are they fearful of? Seemingly the next thing that comes to ones mind is its a duplicate product supplied to me and that is the reason they are not taking it up with the company?.
As a proof i shared the pic comparing the size of Tommy Hilfiger XL size green t shirt ordered from Myntra only few months back with this new orange tshirt and the size difference is huge..still they have point blank refused to take it up even.
My issue number-IN********************