For Months My Family Has Been Battling What Some Doctors

For months my family has been battling what some doctors have thought to be scabies. We have taken all necessary steps: repeatedly dousing ourselves in kwalada p ( wife 5 times, me 4th time today, our kids twice), we have immediately washed clothes in hot and dried clothes excessively on hot, have had our house treated 3 times. After all, I still felt a telltale pinch or prick on my leg a few hours ago. Upon examining, a tiny red spot was evident on the skin. When touched, a small scab, or dot at center fell off and it bled. We keep being "bitten"' even though we never see what is biting us. Please help.