Can you sue a company who bought a domain name the same as your own after you got yours?
If you own the trademark on the keywords/ name of the domain, then you may have grounds to pursue legal action. If it is a generic word/s, then you may struggle to have a case. I would recommend seeking legal advice from someone who specialises in online/ digital law.
Usually, there's an option to cancel the subscription to a domain name if you bought it from a provider. It may be as easy as sending the domain provider an email or phone call. If they won't allow it, or if you signed a contact or agreement that says the domain is yours for an allotted time, they will not take it (Or disassociate it) unless conditions can be agreed upon.