British Citizenship ceremony non attendance

[Baruwa]

I applied for British citizenship on 19/04/2018 and received a letter 27/06/2018 from home office requesting further information to make a decision. I Send all the information and answered the question what they asked. I didn't hear anything from them for while. I received an email on 24/01/2019 stating that they have send me a letter 08/07/2018 that informing my application was approved and contact local register office. However I haven't contacted local office and therefore the register office has Send my certificate back to the home office. But I never received that letter. You can understand how I am hopeless waiting invitation letter every single day. It's been more than 3 months time. They are asking reasons why I didn't contact local office. I emailed and send letter them saying that I didn't receive the letter but I haven received any acknowledgement or replies from home office. I am very stressed and hopeless. I don't know what shoul I do now. If anyone here who has similar experiences or advice would be much appreciated.
Thanks