How to handle a person who lying and didn't do her Promise?

I thought lying is a sin, but why this woman didn’t know this? she use to lie every day, didn’t she know that lying is a sin? 

There is a story in the bible, a couple name Ananias and Sapphira, they lied about their money to the apostle, all of the sudden God punish them to dead, (Act.5:1-11)(http://emmanfbbible.blogspot.com/2013/07/lying.html)

What I’m saying is, if this woman I'm talking about live in the days of the Apostles of Jesus, maybe she dead already.

Well, this woman I'm talking about is our company secretary, she is the one who processes our reimbursements, but she didn’t do her job instead she always telling us that, she will give it to us with in the day, of course, we will expect it, but the night has passed and the morning come, there is no picture of money from her, when you asked her why she didn’t give it, her reason is, she forgot it, almost every day, this is her reason, a week, before she gave it. everyday you have to follow up your reimbursement to her until she gave the money.

Every day you expecting something but it didn’t come true because of the liar person, so, stressful.

I can report the matter to the Big Boss, but if I do this, we will just build a gap between us and our secretary, it's not good in one group. to avoid this problem, here is what I do.

• I keep being patient, Instead of stressing myself because of the liar, I cool down, thinking that I have nothing to do but to keep wait until she gave it.

• I Keep on following it up to her by calling on the phone and texting, almost every day until she gave it.

• I humbled myself, I didn’t fight back on what she doing to me, because I thought, in this way I will touch her heart and gave it to me.

• I make a record of the thing I gave her, like, a receipt of my refund, I photocopy it and keep the xerox before I give her the original copy, so, if the original loss or she denied this, I have my own record to show. Remember, she is a liar. She can deny everything.

• I Pray and believe that I can have it, we cannot force people to do what we want but God can force them to do what we ask, as you do your part in Praying, God will do too.  

If you suffered like me from the people like her, I think you can do the same as I do, as being patient, Patient means content to wait if necessary, not losing one's temper while waiting, a long minded. Let it to God, as a Christian we have God who punish people who do wrong to us.