I need a report to show me any AR that was billed prior to 7-1-2017,  but NOT paid as of 12/31/2018.  Is there a report in TS that will give me this info?  Or a combo of a couple reports that I can then put the info together in Excel?  I use TS Premium

I need this information for calculating the 2nd half of a retired partner's AR payments.  The number I need is the amount of AR that was not collectible as of 12/31/2018, but billed prior to 7/1/2017.  I have our AR balance as of July 1, 2017, and I have our AR balance as of 12/31/2018, but I can't count any of the new AR billed between 7/1/2017 and 12/31/2018, only AR uncollected billed prior to 7/1/2017.  We are not a huge firm, but we are big enough that manually calculating is a long tedious task, and I really don't even know where to begin. I've tried running a Payment register and selecting items paid between those dates, but billed on invoice date prior to 7/1/2017, but it doesn't export the correct info because I am getting data for invoices within the 18 month period that were not generated before July 1, 2017.  I also tried running an AR history by period, but that report didn't seem to give me what I needed either.  I've spent the last 2 days running various reports trying to get the information I need, but have not had any luck.  Does anyone have any suggestions for me?  I need to provide the information to the partners asap, so any advice you can provide will be very appreciated!  Thank you!

Oh, I am using Timeslips Premium and it is up to date except for the service release released today that we have not downloaded  yet.  Thx