medtronic strata keeps losing setting

I am now 58 years old,4 years ago I had a Medtronic strata NSC LP shunt fitted in my head it has now been adjusted at least 13 times because it keeps adjusting itself which is causing major problems with overdrainage its  setting is normally set at 2.5.I am a mechanical engineer & am well read on do & dont's I keep well clear of any magnets etc.I can get no answers from N.S who dont do anything to help just keep adjusting it back.B4 this kills me I am trying to get removed but dont know what to do with the unit when removed Medtronic say they will look at unit when removed but I don't trust them when they report back.I thought an NSC Lumboperetoneal shunt was meant to be fitted in the spine but mine has been fitted behind ear which is shunted in to my 3rd ventrical could this cause the problem my N.S has avoided me since I said a 2nd opinion was needed as they all stick together I dont know wot to do,I have had tubing checked its ok valve has been hard to adjust sometimes & very unstable what can I do.I feel so helpless with this problematic valve in my head.I note on other sites people with similar problems but not as bad.I have been begging for help but am getting nowhere.Would love to hear of any ideas before I do have a major melt down causing a coma or worse death.PLEASE HELP ME!