If and if statement in formula field

If and if statement in formula field

If(Contains('${Leads.Plan Name}','Unlimited 12/1 Mbps'),if(Contains('${Leads.Network Provider}','NBN'),${Leads.Monthly Fee},56.88))

OR

If((Contains('${Leads.Plan Name}','Unlimited 12/1 Mbps') And Contains('${Leads.Network Provider}','NBN')),${Leads.Monthly Fee},56.88)



To assign a value into the field, there are 2 conditions need to be matched. Can anyone help me out with the formula above?