Can you guarantee first place on Google?
No. Rankings depend on relevance, competition, reputation, location and other factors. The aim is to remove avoidable problems and make the website more useful for the searches it should serve.
Why is my page not indexed?
Possible reasons include a blocking directive, duplicate content, canonical selection or Google deciding not to index the page. The correct next step depends on the live page and Search Console evidence; a sitemap alone does not guarantee indexing.
How quickly will changes work?
Google needs to crawl and process changes. Some fixes may be reflected sooner than wider content improvements, but there is no reliable universal timetable for ranking growth.
What information should I send?
The website URL, services and actual service area, the searches you care about and any Search Console messages. I can assess the site before deciding what additional access or work is needed.