Sorry to hear about your plight. THis just brings a thought I've managed to carry w/me my entire life. I don't buy anything leather because it sticks to you in summer and is cold in winter. I know this 'advice' doesn't help you but for the benefit of others, I thought I'd mention it. (None of my cars had leather seats either.)
Anyways, leather is usually dyed, or tanned. If it's 'cheap' leather, I'm sure you'd have this problem. The only advice I can give you is to look for a label on a cushion or on the bottom-side of the sofa for a mfgr. or something. Maybe it's 'stamped' on the material somewhere. Perhaps you can revisit the store and have them pull your receipt from the basement to find out who the mfgr. was. THEN, call them. Furniture usually has 'Model Numbers' (or letters) so look for that too.
My best to ya and hope this helps.
Jay J -Moderator
PS: I've never heard of this happening before so I am curious as to what you end up having to do and what the mfgf. actually says ...