Problem resolved. First thanks to everyone for your input on this issue. It has been a real learning experience.
The customer finally contacted me and was ready to give up and asked if I would come on site to try to figure this out.
1. I tried reversing polarity and no change, still dropped calls on hold.
2. On hook voltage was 76.7 vdc, off hook was 52.1 vdc, and loop current was 13.99 mA.
3. Do you know how hard it is to get ahold of someone at "the phone company" who even knows what a "fx" line is?
4. One hour later I've got a trouble ticket for a dso circuit 34UCPAXXXXXXXXXX.
5. Tester calls me back and says "everything looks ok".
6. I asked if line voltages are supposed to be like this. They weren't sure.....
7. Tech is dispatched, on site he says circuit seems ok and he has no way to adjust the voltages.
8. After explaining that there is another "fx" circuit on site with no problems, they compare the two, and tell me one is a 34 UCPA and the other is a 34 UCNA. Interesting enough the other circuit is 52 vdc on hook and has 23.5mA loop current. They will get back to me.
9. Five pm, trouble is resolved, they first tried to lower the gain in an "mst", and finally removed the "mst" (repeater?) from the circuit. I forgot to mention the address was 18000 ft from the co, and was copper end to end.
10. Customer tested multiple times, and call never dropped.
11. Amazing!......

Thanks again,
ictelco