I've seen this happen even with accounts that looked completely normal. Before sending an appeal, go through everything carefully billing details, business information, landing pages, and any policy-related settings. Sometimes the issue isn't the ad itself but something that affects the account's trust.
For the appeal, keep it short and factual. Explain what you were advertising, mention that you've reviewed the policies, and list any changes you made if you found something that could have triggered the suspension. Generic or repeated appeals usually don't help, so it's worth checking everything first.