It's completely depending on current website status. If website brand new then ranking will take time and if your website optimize and a bit old then can take less time.
SEO link building services are not planning of one night. Generally for few months we need to update website according to targeted keywords, then wait for crawlers or bots to index website structure, contens and changes. Its also depend on number of works on website and search engine bots frequency to visit website.
In short at time can vary between least 3 months to 12 months to get desired ranking in search engines.
Note one thing guaranteed ranking meaning, you will see good results in SERPs, organic traffics and online popularity. We are not saying about #1 result because no one reputed company can give you guarantee for #1 position.