Symantec exec 2015 media tape compatabilty

Hello

I have an open case with Symantec support 9004592 but I am not getting the answer i need. I recently baught a brand new HP server running 2012 r2. With a HP tape Library Hewlett Packard LTO Ultrium-5 MSL G3 2014. My supplier also sent LTO 6 C7978A media tapes.

After getting errors regarding barcode compatabilty and not being able to inventory or write to the media, Symantec tech support discovered our media tapes are not compatible with Symantec 2015. 

What I need to know is what media tapes are compatible with Symantec 2015 and my HP tape library

We have called them twice and sent several emails unanswered, can anyone help.

Thanks

Gemsley