Just out of curiosity, may I ask why it is imperative? What kind of products are you selling? Kanji brand names are NOT common in Japan, especially those that are regular existing words like 寄与 or 貢献. Those look unbelievably self-important to me, who used to be in the fashion business. I seriously could not think of a product line that would appeal to the Japanese market with a brand name like the two above.
Any reason you guys do not want to go with the katakana for "Qontribute"? That would be the normal route to take for foreign brand names.