Browsers not resolving URL names

Hi Folks;
My ISP has joined a nationwide dial-up service and uses a new phone number.
The old phone number is still active (until Dec. 1) and both Netscape and Lynx
have no trouble accepting a URL name and converting it to a number. The new
one just states that it is "unable to locate the server". Also has similar
problems when I try to obtain my mail. The tech at the ISP has no clue as to
what is causing this and no solution. Any assistance will be greatly
appricated.

TIA
Clay Stapleton

PS: I did get Mozilla to work on a Debian distro on another computer.