Unhappy employee

I've been working for the company for the past 8years now but I'm still working for the same hours . I tried to log a complaint at their HR ,but they told me ishoul talk to my manager. My manager hires people while I'm still in the company with higher hours contract and it's not fair to me ,it feels like I'm not recognised. We all want growth when we work in a company not to be sidelined like that.