Hello Mr Khan,
It is already 6 days since I raised the issue and you was giving me suggestion instead of physicaly looking into it such as removing the phone pattern yourself and test.
I am sorry but I was facing a lot of pressure from my client too. The bug on the Form builder is that when you add a new text field, upon submit, it says "Please fill in the requested format". As a work around, instead of adding new field, I duplicated the existing default text field and edited it. It worked.
I am sorry if I was rude. I wish you Eid Mubarak.