3 hdd failed in an array

Dear

there is 3 hard drives failed in my areca stiorage with raid 6 and the one of the logical drive is not accessible

any solution can suggest to get the data
the manufaturer didi everything and suggesting next option as data recovery

one data recovery team asking me too much money for recovery

what is the best can suggest

  1. physical dta recovery ?
    or
  2. logical drive repaire ?

please help

do you know y HArd disks are getting failed frequently

any solution or any option to find what is the reason of it ?