mum4ever has the key. It's all about chemistry. I never had a prob. like this until last year and I tried everything including washing with different types of soap several times a day. And of course many types and times with deo.
When I put vinegar (organic/aged, Braggs or Eden are good) in my diet it changed a lot. Put a few tbsp. in a small amount of water and drink, if you can't do it, then add raw honey. Slow increase your intake to two or three times this amount.
Until then you can try using hydrogenperoxide on a cotten ball or cloth after washing. Let dryr and then add deodrant. I did this too and it helped considerably. But I had to do it a few times a day at first.
Give it a try. Good Luck!