I need a need root certificate

I hope an explanation of what a root certificate is will help your understanding. Root Certificates are saved in the Certificate Trust Store on your phone; it is a file installed along with iOS. The Trust Store contains the digital signatures of issuers of the SSL certificates that are used to encrypt access to websites and email servers. There are billions of SSL certificates in use around the world. They are issued by a relatively small number of agencies and companies (Called Certificate Authorities, or CAs), who, as part of the process of issuing the certificate, verifies that the site is legitimate. When you visit a website the certificate from that site is sent to your browser. Your browser then verifies that the certificate was issued by one of the agencies whose signature is in the Trust Store. If the signature is not in the trust store you see a warning that the site may not be what it seems.

Thus, all the root certificates that your phone needs are already on it, and can’t be compromised.

Why do you think it’s compromised?

They don't know what they are talking about. you do not need a "new root certificate".