Costwise does qualify as word, because the -wise suffix is productive; that is, adding -wise forms an adjective or adverb of manner. Dictionaries often don't individually list words formed by productive affixes.
Where the resulting word is awkward, like security-wise, which is actually quoted in Oxford Dictionaries, it can be hyphenated. Hyphens are gradually going out of fashion, particularly in simpler words where the components are readily identifiable like costwise. As ODO states, "most of the words so formed are considered inelegant or not good English style."
There is an issue with its placement in the sentence, though. Costwise is not an adverb which can precede the adjective it qualifies: it must occur after it. This applies to most, if not all, -wise adverbs.
high-quality, competitive services costwise.
This is what makes it "inelegant, not good style".
In this example, you are describing that the services are competitive on cost, so you could simply form a compound adjective:
high-quality, cost-competitive services
This has the effect of coining a little bit of business jargon, which may or may not be desirable.