Need help on warranty packing of 1 TB external HDD USB 3.0

My HDD is not being detected by laptop or any PC, sometimes if it does, the PC hangs.

It’s in warranty, I’ve generated the RMA No. and asked for Courier pick from HOME

MY QUESTION:
The Packing instructions tells to use 2 Inch Thick Bubble Wrap, i don’t have any, I can Get, but I have One 5 Inch Thick Sponge, from all sides, i can cut in middle and put the HDD, it wud be Very safe, but than is it OK?
On this point can’t WD reject ?

I’ve rest of stuff, two copies of RMA pre-Mailer, one inside, one outside. Writing RMA no. on three sides of the carton which has the HDD.

Please Help, much appriciated, Thanks in Advance

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