Hello,
Please provide temporary wp-admin access so we can take a closer look.
Also, provide links to pages and describe how breadcrumbs should look there.
Breadcrumbs size option in Theme Options -> Breadcrumbs was removed in 5.0 theme version.
Breadcrumbs size you can change via Breadcrumbs paddings settings http://prntscr.com/l4bpgy
Regards