Nexus 4 auto dialing extension does not work

I used to own a T-Mobile Mytouch 4g before, which had the pause character before extension otherwise '*p*' on that handset and it was working fine. Now, I own and use a Nexus 4 and I understood that the pause character on the Nexus 4 is '*,*' (*a comma*). I replaced all the contact entries that had a '*p*' with '*,*' (*a comma*) in my contacts. And now it is not working, basically, what happens is when I make the call using that contact's number, the number gets called but the extension is not dialled automatically. Anyone would know how to fix my issue?