Thank you for your question.
Taking the ipill can be associated with unscheduled bleeding or early or late periods. There is no way to make the periods come on time. She will have to wait till they come or do a pregnancy test if they are delayed.
The ipill is an emergency contraceptive. It can never be as good as regular effective contraception in preventing an unwanted pregnancy. Using a reliable contraceptive takes the guesswork out of preventing a pregnancy and predicting periods. There are several to choose from in addition to condoms. Condoms are very good at preventing infection but the failure rate in preventing unwanted pregnancy is unacceptably high ( because couples forget to use them or they tear or slip). Her gynaecologist can help with recommending a suitable reliable method.