Bit-locker issue

I have WD external hard drive which is locked through Bitlocker, I had unfortunately forgotten the password so I use to unlock the hard drive through recovery key. The machine on which i was able to open my hard drive was win7 and it got bad, hence I have a new laptop however I am unable to unlock the hard drive using the same recovery key so I came across a third party tool called M3 recovery and for some reason I was able to unlock the hard drive using this software with same recovery key which is quite strange to me
However after retrieving those files I am unable to open them it say bad file or not supported ( example, pdf, excel, word, JPEG) could you please advise how i can recover my data and how will it cost to take your service ?

Requesting if any one can advise or suggest or troubleshoot through team viewer then I would really appreciate your help