have you paste the exact same string as you are getting from webservice because their should be some uniqueness between tags. like NAME:suresh kinta and Section:2D their are 4 spaces and after section and age their is only one space. Otherwise you would have used simple Replace method to solve it.
If the number of spaces are unique after each tag than you can do it like this. suppose number of spaces after each tag is four. so i will replace those four spaces with line break.
string a = what Ever You Getting From WebService;
a = a.Replace(" ","<br>");
Response.Write(a);</br>