Learn English – use two colons in a sentence

It is ill-advised to do so, and in your particular case you would be better off removing both colons entirely.

Multiple lists in a single sentence, though not forbidden, is not advised in writing, as it leads very strongly towards run-on sentences. Colons, when used to start a list, should particularly be used sparingly, as they denote a definite list of items separate from the sentence itself, and using multiples of them leads to a very cumbersome and difficult to read sentence.

In your case, these colons are not even needed, since each individual numbered item is in a list of its own. If you wish to keep all of the information on the same line, removing the colons entirely and leaving the sentence otherwise unchanged is advisable.

If you are going for the highest level of clarity, you could instead create a short numbered list.

'These are hugely important factors for S. Oliver Canada as we’re dealing with a brand that:

1. Is unknown in our market
2. is known for low prices"

But even this is a bit more complicated than you truly need.

For your sentence, a list is not actually required at all

You only have two items of interest. So it would be a far better idea to just name those two items.

"These are hugely important factors for S. Oliver Canada as we’re dealing with a brand that is unknown in our market and that is known for low prices."

This however is starting to verge on writing advice instead of grammatical advice. But in short - when you are writing and want to convey information, to get the greatest effect, use the fewest words. Or as the saying goes, 'less is more'.

This may be more of an extended comment than an answer, but the cited rule (if I understand it properly) seems illogical. Sentences can end in verbs. So, if colons can come after complete sentences, then colons can come directly after verbs.

For instance, here’s a sentence from this week’s Economist:

Lviv displays formidable discipline and self-organisation in its self-policing: taxi drivers use their radios to report anything suspicious.

If we replace in its self-policing with in how it self-polices, then we have a verb directly followed by a colon:

Lviv displays formidable discipline and self-organisation in how it self-polices: taxi drivers use their radios to report anything suspicious.

Here's another example of one of their sentences and a paraphrase that ends up with a verb + colon:

But the two sides should not overdo it: they need each other.

But the two sides should not exaggerate: they need each other.

Maybe the rule needs rephrasing—or abandoning.