I parsed your example file "exportedChart.emf". That's what it contains:
Horizontal-Resolution = 141.7674
Vertical-Resolution = 141.402
Frame-Width = 8599.916
Frame-Height = 5747.963
Bounds-Width = 480pix
Bounds-Height = 320pix
■ 000-EmfHeader: At=0, TotalLength=108Bytes, DataLength=100Bytes
Bounds: Lft=0, Top=0, Rgt=479, Btm=319
Frame: Lft=0, Top=0, Rgt=8582, Btm=5730
Device: Wdt=1920, Hgh=1080
Millimeters: Wdt=344, Hgh=194
Version: Major=1, Minor=0
◙ 001-EmfGdiComment: At=108, TotalLength=44Bytes, DataLength=36Bytes
► EmfPlusCommentIdentifier: EMF+
● 00 EmfPlusCommentType: EmfPlusHeader
Size: RecordSize=28, DataSize=16
Resolution: DpiX=96, DpiY=96
Meta-data: Signature=DBC01, GraphicsVersion=GraphicsVersion1_1
◙ 002-EmfGdiComment: At=152, TotalLength=7296Bytes, DataLength=7288Bytes
► EmfPlusCommentIdentifier: EMF+
● 00 EmfPlusCommentType: EmfPlusObject
Size: RecordSize=7228, DataSize=7216
Identity: Continued=False, ObjectID=0
- PlusObjectType: ObjectTypeImage/not serialized
UNKNOWN EmfPlusObjectType
● 01 EmfPlusCommentType: EmfPlusDrawImagePoints
■ 003-EmfSaveDC: At=7448, TotalLength=8Bytes, DataLength=0Bytes
■ 004-[EmfSetIcmMode]: At=7456, TotalLength=12Bytes, DataLength=4Bytes
■ 005-[00000015/15]: At=7468, TotalLength=12Bytes, DataLength=4Bytes
■ 006-[00000015/15]: At=7480, TotalLength=12Bytes, DataLength=4Bytes
■ 007-[00000051/51]: At=7492, TotalLength=153964Bytes, DataLength=153956Bytes
■ 008-[EmfBitBlt]: At=161456, TotalLength=100Bytes, DataLength=92Bytes
■ 009-EmfRestoreDC: At=161556, TotalLength=12Bytes, DataLength=4Bytes
DC: most recently saved
◙ 010-EmfGdiComment: At=161568, TotalLength=28Bytes, DataLength=20Bytes
► EmfPlusCommentIdentifier: EMF+
● 00 EmfPlusCommentType: EmfPlusEndOfFile
Size: RecordSize=12, DataSize=0
■ 011-EmfEof: At=161596, TotalLength=20Bytes, DataLength=12Bytes
PalEntries: 0
This is actually one bitmap. Tell your programmers that they are not creating emf files correctly