TPR/Serving Question

I have a question for those who may know. A little background: We are in KY and have a FS, 3 and FD, 7 with autism. Our kids were removed from BM Feb 2015 and placed with family. They entered foster care April 2015 & had one placement prior to us. They have been with us since 7/10/2015. So as of today, removed from BM 21 months, in foster care 19 months, and with us 16.5 months. Goal was changed to adoption in June 2016 after giving an extention for being gone to rehab. TPR was filed mid July 2016. She had visits every 2 weeks, 2 hours, supervised by SW in DCBS office and hasn't has phone calls in over a year. However, after making our FD upset every visit and missing 3 of 4 (no visit for 6 weeks, then 1, then missed again) courts ordered them stopped. They are still trying to serve BM because she was hit and miss with visits, she moves around, and has no job. BD has never been in the picture and refused a case plan, he hasn't had contact in the 21 months and has been served. So, my question is... What happens if they can't find her? Do we have to wait until she is served or is there another process? They've been trying to serve her since August.