You must also put the request in quotation marks. The "&" character is otherwise interpreted by the shell (execute task in the background) and is no longer part of the request for curl. Therefore your request is always truncated at the "&" character and you always see the same page.
So the right thing would be:
curl -i -k -H "Accept:application/*+xml;version=31.0" -H "x-vcloud-authorization:f9c49bfdghkjkfgd4ebf4d7e2d89c17b" -X GET "https://my-vcd/api/query?type=adminUser&page=2"