I think you are refering about App problems and no theme applies ploblems.
Check and try to delete data and caché
GO settings / Applications/ Galaxy Themes on the list/ store/ and delete both.
Also be sure it is join to Samsung Account registered.
Explain us a little bit your problem, when, how, where started the problem that you mencioned.
Thanks, I wait than other people can tell you more 
It's better to post in the adecuade Thread, others smartphones thread is our space for it
