I recently bought their most expensive Effortless model and had some trouble with it.
The only way to contact support is to email an address at sleepphones.co.uk. I tried that and got an out of office message back from somebody at go10.co.uk. They didn't say when they would be back, but they did mention another 'team' email address at go10.co.uk, so I emailed that. In reply I received a different out of office email from someone saying they were out for the rest of the week but somebody from the team would get back to me. They didn't.
There is also an 0800 number on the website for sales, so in desperation I tried that. It went to an EE mobile voicemail.
It seems pretty clear that SleepPhones UK has outsourced their UK support to go10.co.uk, so I searched my Linked-In contacts for go10.co.uk and their Managing Director was there, so I messaged him for help. He didn’t reply, and instead simply blocked me.
So by all means buy some SleepPhones, but don’t expect any help from them if you have a problem. Instead, you will have to do as I will, and go to your credit card company and dispute the charge.