Strarky Evolv AI 1600 problem

I got a pair of Strarky Evolv AI 1600 for free through my health insurance. It has four programs: automatic, restaurant, Music and induction loop. What drives me crazy is the pumping noise in all of them except for the induction loop when there is some noise in the surroundings. Tomorrow I have an appointment with my hearing care professional. What can be the cause and what can she do about it?