At the Marchall website you can buy new ear cushions for the ANC. The send a SET in 1 package. Opening tip: see "replacing the battery". You need some precision and pressure to place the new ones. I did use a screwdriver to click it back from the inside all around. Look carefull how it clicks back and be patient.

After replacing the battery, this Marchall Monitor ANC II headphone still does not load the battery as it should.

You can load the battery fully, but when you release the loading cable, the battery shows 0% again.
A factory reset did't solve the problem.
Ditch the headphone from the Marchall app and connect it again like a new headphone didn't solve it either.
So i got stuck with a 2 year+ old (not cheap) headphone that does not work any more.

Mmmm, you can still use it with the 3,5mm cable but then you have no ANC.
I read that lot of people have this problem, we need a solution otherwise all the headphones are becoming waste.