I used someones link to join bulb. It will be complete on the 14th, how will I get the £50? Will it be put into my bank account or my electricity, because Bulb doesnt have my bank details and I dont know how to give them it either?
You mention “put into my bank account or my electricity” by which I assume you mean you have a pre-pay electricity meter?
This means that you’ll receive the funds via a payment through transferwise. You should get an email from them at some point regarding it, but it seems that it often doesn’t work so if you’ve heard nothing a couple of weeks after your switch has completed do contact Bulb to chase it up. You’ll need to do so via private communication and not this public customer forum. Contact details are available through the Help pages linked above.