hi,
By purchasing a Reseller web hosting plan from cpwebhosting.net, i want to start a web hosting company. can i advertises my own web hosting company as the actual service provider?

yes, u can do it.

when the hosting reseller advertises his company as the actual service provider, and does not use the name of the actual underlying web-host provider it is called Private Labeling. This way the customers do not know who the actual provider is, and do not try to go around the reseller for a better price. In most cases, the customer does not even know that he is using a reseller.