There is an option to change your mobile no, but it will ask you to link employee details to adhaar or pan card and again the name of PF and mobile number has to match, else the problem continues.
I think in 1st case the adhaar has to be linked to your new mobile and then, linked to PF. but to link adhaar to new mobile number, you should have either old mobile number or again have an personal email address linked to your adhaar to get OTP.
But , both are missing , then you have no choice but to go to adhaar centre and get the new mobile number updated there.
I hope i could throw some light on the issue.