Upto now I am £450 in credit, have emailed bulb for instructions to reclaim it back but no response. Any ideas?

If you search the help pages for “refund” you’ll find the information on how to claim some of your credit back. However, you’ll see it tells you to email Bulb which you’ve already done. How long has it been since you emailed? If it’s been over a week I’d chase it up by either phone or webchat.