There's a lack of context here, which makes it hard to understand. We need to see more of the text to fully understand the context of sentence. However, it's easy to explain what 'de-brand' means. It means: un-brand; remove branding; remove brand naming; return to non-branded products; etc.

Here's what the dictionary says: Debranding (de-corporatizing) occurs when a company removes its name from its logo for a marketing campaign. This is usually in an attempt to make themselves appear less corporate and more personal. Debranding (transitioning into "generic") occurs when a company with a well-known brand opts to appear more generic. This means the company will eliminate advertising and reduce prices and debranding in this sense can increase profit margins. hope this helps :)

To remove a brand (or brands) from the company. I believe it is acceptable to spell it as "debrand". I am not sure as to why it is hyphenated.

Yes, really. If you adapted it, you may have inadvertently changed the meaning. It's vaguely possible that in some strange context it may make sense, but without that context, it is nonsense.

Really!? It's adapted from an IELTS propitiation book! At least I've known that means nothing. Tnx