Can pregnancy occur after taking i-pill?

Hi doctor,

My wife got her periods on 25th and on sixth we had unprotected sex followed by i-pill, which she had within four hours after the act. On seventh, we had protected sex thrice with new condoms for each act and after each act she washed herself with water. On thirteenth, she had bleeding for three days similar to her periods (around 60% of bleeding) but with less flow and few clots in them. These three days the bleeding was on and off. Her periods were to be due on 25th. We did a home pregnancy test that week and the results were negative. After ten days, we got the second pregnancy test done, but still the results came negative. At last on fourteenth, we got a urine pregnancy test and the result was again negative. She has no symptoms of pregnancy. On 17th she felt cramps and abdominal pain that was followed by thick white discharge. Is it a sign of pregnancy? Or is it a sign of her periods? Or is she pregnant?

Please guide.

Thank you doctor,

I would like to know, till when she should wait for her periods to commence? Is it normal to have delayed period? Do we have to repeat the test? Should we consider 13th as her period or 25th as her period date?