Calling a WebAPI in c# and using the response

I wanted to get information from an API and use in my c# programm, but I have no clue how to do it and find nothing on the topic, even tho I suppose I should...

So I'm given this information:

API URL:http://ift.tt/2F4eWah
Charset：UTF-8 
Method：POST/GET Suggest use POST 
Submit Data：action=xx&parameter=value....

Parameter:

[username] : you username in our system,like xxx@gmail.com
[token] : like 12312312token123123123

1.Login and get acc summary

1) Submit: action=login&username=[username]&token=[token]
2) Return: [username]|[value]|[integral] 
3) Example: xx@gmail.com|10|10

So I guess the submit data should look like this: action=login&username=email@gmail.com&token=123123123token1231231 and I should get something in return in a string or something like that to reuse... I wrote something on it but its not working at all and I don't know what to do. Help would be greatly appreciated.