Hiring a hacker to help you gain access to another device depends on various factors which I'll briefly highlight in this answer before I proceed to guide you on how to hire a hacker or how to hack another device by yourself . 

To Hire a hacker for such job you need to take into account legal consequences first in most country this is illegal and come with strong consequences , which brings us to the next factor to consider which is the type of hacker you want to contact for this type of job , there are the white hat hackers , the black hat hackers , the grey hat hacker and red hat hackers . The white hat hackers are the good types of hacker and they will never accept such jobs because of the legal and moral reasons , the black hat are the ones best sorted for this type of jobs because the are drawn to any form of illegal job as long as the pay is right , the grey hat are stuck in-between the white and black hat (they can not be trusted because the might grow a conscience and turn you in or even tell the owner of the device you hire them to hack about your intentions) . The red hat hackers are interested in hacking a hacker to see who's more skilled so if you ever have issues with a black hat hacker just get a red hat hacker to defend you .

 Finding hackers for jobs like hacking into a mobile device is another tricky aspect because you can't just hire anyone on telegram or social media 99.9% are scams , because of the nature of what they do black hat hackers like to stay hidden so you need to know your way around the dark web to find them or another good option is you can use keywords like   (anonymous hackers hire gigabyte1) on google , this will bring out the top best place to hire a hacker anonymously usually the fast site on the search is the best because it means thats where most people visit  , I recommend you go for sites with a 100% money back policy so you're protected . In my opinion this is the best way to find professional blackhat hackers to hire .

After you have found a hacker and agreed on a fee , I must mention that on no account should you send upfront payment directly to the hacker no matter the explanation he gives , most of the websites that offer money back policies have a very secure escrow system , simply initiate an escrow transaction between you and the hacker , a real hacker will complete the job if you initiate escrow transaction . Another thing to remember is never release payment to the hacker from escrow until he has completed the job to your satisfaction (you need proof that the job has been completed before releasing payment ), If the hacker is the real deal they can give you a temporary access to monitor the device for few hours as proof , or they can send you contents from the target's media that shows they have indeed gained access into the device . This hacks usually cost between 350$ - 600$ on the dark web prices maybe more depending on how long it will take and how complex the job is for the hacker . 

I hope this information is useful to anyone looking to hire a hacker , also please I'll like to state that this information is for educational purpose and I take no responsibility for any outcome resulting from actions carried out with the above information .