No decision/invitation received, but certificate with council

Hi All, I applied on 08/02 and haven't heard anything from HO at all. Randomly I've found out that my naturalization certificate has been received by my local council on 15/07. I never received any decision or ceremony invitation email or letter, nothing in spam folder either. Tried to call HO multiple times, always asking me to send an email, which I have sent to maybe 4-5 different email addresses I found on the forum. I haven't received any response do far and it is about 2 weeks since I sent those emails. Council refuses to book a ceremony until I receive the ceremony invitation letter. But surely, it will be 4 weeks since they received my certificate, so the ceremony letter must have been sent out already as almost everyone says that it is being sent out roughly at the same time as certificate? Is there any way out of this? Is there any HO number where I can actually talk to someone and they will have a look at my case? Or should I complain to my MP? I am trying to sort this out for 3 weeks already but getting nowhere.