I have exactly the same issue. It connected when first used but never again. I have paid the 18 pounds for support just to be told it is a hardware issue. I got the money refunded. I have advised HP that this is a common issue and that it is fair to say the fault was on the unit when purchased. I have been waiting for so called private message for almost 2 weeks and it came today. I will copy it at the end of this. Basically my sprocket is now 4 weeks out of warranty and they are not interested. I can't believe they won't help me in some way under the circumstances. 
Oh well. I'm not hard up for 100 pounds so can't be bothered to push it. HP on the other hand obviously are!!!
Good afternoon, Kevin
Thank you for taking the time to speak to me on Wednesday.
We have received confirmation that the amount you have paid to receive support has been refunded to your PayPal account.
Unfortunately, as your HP product is out of warranty, we are unable to further assist.
Thank you for your time and cooperation throughout this process and apologies for any possible inconvenience.
KumarThank you ever so much for listening and taking the trouble to forward my issue to someone who may be able to help. I only want what is fair and reasonable. I don’t nine paying out more money but I really don’t want to have to just write it off and throw it away. Kindest regards Kevin.
@KevinMcclaughliKUMAR0307 I am an HP Employee
As I do not have an option to replace/service the unit, I have brought your issue to the attention of an appropriate team within HP.
They will likely request information from you in order to look up your case details or product serial number. Please look for a private message from an identified HP contact.
Additionally, keep in mind not to publicly post personal information (serial numbers and case details).
If you are unfamiliar with how the Community’s private message capability works, you can learn about that here:
Thank you for visiting the HP Support Community.
Hi again Kumar and thank you for coming back to me quickly. I do appreciate you have procedures to follow etc but I have to reiterate my case because I feel this sprocket has failed at an unreasonable time and it has failed with an issue that appears to be very common. Kumar, please just ask yourself this question……If you bought a sprocket, used it once then it wouldn’t connect when you next tried to use it and you spoke to the manufacturer and they said they wouldn’t help, wouldn’t you be upset and annoyed? Then if you looked around on the internet and realised this was not just a one off failure and there were a great many other people with exactly the same problem as you, would you not now think that you had been sold something that was of un – merchantable quality? If the unit was still under warranty you say your team would have replaced it. If you look at the dates and facts surrounding my issue it actually failed on Christmas day. I spent a long time on this site looking for help to get it connecting and I finally contacted best to serve on 30th December 2019 who raised a case etc. At this point in time it was only 5 days out of warranty. Surely a company such as Hewlett Packard can understand that it is not right for this sprocket to fail 1 week out of it’s warranty period. Especially as this is such a common and well documented failure. There are a great many people on this site and other blogs that have suffered the exact same problem. That is that the unit works once, as it did for me last Christmas, then when you try to use it again later it will not connect.Is there not a policy for goodwill in this line of situation? I mentioned earlier that Hewlett Packard won’t help me. If the reason was that they can’t then I would understand. But so far there is no reason why they can’t help. They just won’t and this is very annoying and wrong for a company of your size under the circumstances. Kindest regards to you as always though Kevin
@KevinMcclaughliKUMAR0307 I am an HP Employee
I understand your concern. As you have already tried all the possible troubleshooting steps and the issue persists, it is concluded to be a hardware issue with the unit.
If the product was under warranty, HP Support team would have replaced it for you. As it is out of warranty that will not be possible now. Since you have already contacted the HP escalations team, support options are limited.
Keep me posted for any other assistance.
Hi KumarAll I need to know is if someone at HP can help me.My sprocket won’t connect to Bluetooth.It has only ever worked once.I can’t upgrade the firmware because it won’t connect to Bluetooth.I have tried many resets.I have tried to connect to it with other devices.It is only a few weeks out of warranty but I feel it should not fail this early on with a hardware issue that was probably present on it from new.So. Is there please anything that you can do to help me? Kind regardsKevin