Some rough Google search shows:
一週間後に解約する (✓)
一週間後で解約する (☓)
but:
一週間後にの解約 (☓)
一週間後での解約 (✓)
If that's right, why is that discrepancy?
Questions below seem related:
What's the difference between に and で when speaking of time of an action?
和訳
少しググった限りでは、
一週間後に解約する (◯)
一週間後で解約する (☓)
に対し、
一週間後にの解約 (☓)
一週間後での解約 (◯)
なようですが、誤りでなければ、なぜこういうふうに食い違っているのですか？
以下の質問とも関係がありそうです。
What's the difference between に and で when speaking of time of an action?
Taking Actions at Specific Times:
Plain and simple, what governs the particle choice for expressing the time of action is the part of speech that follows the particle -- nothing else.
Use に with verbs:
「[一週間後]{いっしゅうかんご}に[解約]{かいやく}する」 = "to cancel after a week"
「5[月]{がつ}に[渡米]{とべい}します。」 = "I am going to the U.S. in May."
「2[年前]{ねんまえ}に[結婚]{けっこん}しました。」 = "I got married 2 years ago."
Use の or での with nouns:
「一週間後での（or just の）解約」 = "a/the cancellation after a week"
「5月の渡米」 = "a/the/one's visit to the U.S. in May"
「2年前の結婚」 = "one's marriage 2 years ago"
Exceptions:
Certain time words do not take a particle when followed by a verb or verb phrase, but even with those, you need to place a 「の」 when followed by a noun.
Those words include: [来週]{らいしゅう}、[先週]{せんしゅう}、[来年]{らいねん}, etc. = next week, last week, next year, etc.
Correct: 「来年[行]{い}きます。」 = "I will go next year."
Incorrect: 「来年に行きます。」
Correct: 「先週の[旅行]{りょこう}」 = "one's trip last week"
Finally, regarding combining particles:
「にの」 is just not a possible particle combination at least in standard Japanese.
Possible combinations include: での、への、へも、とも、のも、でも、にも, etc.
I will not give examples here as it would be off-topic. If asked as a separate question, I might post an answer. Just mentioned it because you used 「にの」 in 「一週間後にの解約」, which is an incorrect phrase.
