Recordcox Error 19

Hello all,

I had one lisence key , used for 2 laptops (windows and Mac) with version 5.8.7 (did not want version 6).

For a technical issue with my windows pc , i had to do a format! Now i am trying to install record box again , 

i receive error 19 (this key is used by another account), i entered with my account , i dont know how to deal with this right now....