Yahoo mail recovery number

I just install yahoomail at my phone..when i try to login system say for security reason they will send login comfirmation to my old contact number..my problem is i no longer use the phone number..i know my id n password..its just my 1st time try to login from my phone..& now i cant login from both my pc n my phone...anyone know how i can get my account back?i understand its for security reason,i install the yahoomail to my phone coz i thought it would be much easy for me to use but now i cant even login to my account