SEO is a long term process that works overtime. If an SEO company tells you they can rank you overnight then they're lying.
There's no guarantee that they can get your website to the top of google overnight or anytime.
It takes from 90 to 180 days to rank content in google.
So that means it can be from 3 to 6 months before content you write might rank in google search. And sometimes it can take longer so don't be discouraged.
I've had a blog post take a whole year before it ranked and was found in google search but now it's continuing to rank.