How can I change my reachable number on fact time

HI ,

when I am going into the setting of my iPhone facetime I see the option called you can be reached by facetime at

+91 xxx-xxxx , I cloud and and apple id email address .

the number which appears ther its wrong and I am not able to change it , basically the number which appear ther was my temporary number which I used it once while i was travelling,

I wanted to know how can i change that number.

since that change happen I am not able to send or receive text from imessenger on my laptop.

the error which appears on my lap top is " your phone must use the same iCloud and facetime account " where as I have same ID used on my both devise .

Can any 1 help me please ....

BR
Saif