Itemized Deduction vs Standard Deduction and Tax Refund

I completed our tax return but have not filed because I see that we barely got a tax refund of about $300.00 instead of some thousands that we used to get in previous years.

 

We have an itemized deduction of about $40,000 and a standard deduction of $27,000. We spent over $13000 on charity and over $16000 in mortgage taxes. I had thought we would get a good refund in our tax return this year but we got about $300.00. My wife and I are retired and living on a pension and social security.

 

What is responsible for this poor refund? Did I do anything wrong in filing?