Veritas backup is taking much longer time to complete

Over the last few months, the time required to backup our system has increased from 12 hours to almost 20 hours.  The size of the backup has not changed.  I have attached 2 screen shots showing jobs completed in April and jobs completed in July.  We are a 501 c3 non-profit and at this time we cannot afford to replace our current backup with an alternate solution.  We purchased the Veritas product through TechSoup and have been told we are not entitled to support but any assistance would be appreciated.