If you done jio number televerification by calling 1977 than you have activated both internet and call service.
I also unable to generate otp on alternate number after facing this issue I went to jio shop where I purchased jiofi device, using jiofi sim in lyf handset I created jio login id and password than on jio login in profile setting I save my alternate number two time in home and work column. In home 1234567890 and in work +911234567890 and after saving I inserted sim in jiofi and easily generated otp.