You can use any temporary mail to quickly max out your referral bonus storage up to 800GB free.
I use https://www.fakemail.net/ or any temp mail of your choice.
promo code 40 gb isn’t working gives 10 gb.anyway thx for sharing.
for those who sign up can use THIS LINK to gain 10 gb storage.for now supports box,google drive,dropbox,onedrive - coming soon.