Calls Going Straight To VoiceMail

[#1]

Having recently lost my job I am back in the Jobs Market & I am frequently getting eMails from Agencies & prospective Employers saying that they have tried to call me on both my Mobile & Landline, but they are going straight to VoiceMail.
Occasionally there is a VoiceMail there but more often than not it doesn't even show up as a missed call.

I know for certain that the phones have not rung nor have I been on the phone at the times that the calls were made.

Having not really required quite so many Incoming Calls until now I don't know how long this has been going on for.

However, this is not affecting ALL calls, as I am still getting calls coming in, only not on a reliable basis.

Because of my now looking for work the reliability of incoming calls can mean the difference between getting a new job or not, so it imperative that this service is reliable.

I called Customer Service, but no answer.  By the time I gave up waiting for a response after 30 mins, the Online Chat was closed as well.

(edit: This post was apparently changed because of supposedly invalid HTML in the post.  I never used ANY HTML in the post)

[#2]

Hi @FourPart, thanks for getting in touch and I'm sorry to hear you're having calls go straight through to voicemail or not come through at all recently. Firstly, when checking your landline from this side we're not detecting any underlying faults or issues. I'd advise then, running through a few checks your side that will hopefully narrow the issue down further.
Firstly, I'd recommend trying to replicate the issue in ringing your landline and seeing if you can get an instance where it doesn't ring and goes straight through to voicemail. If you could please also confirm if the phone rings before reaching voicemail or if it goes straight there?
If the phone rings but goes through to voicemail, then I'd recommend trying another phone to see if the issues persist.
Let us know how it goes.

In regards to the mobile issues you've been having. If you have mobile service with us also then please drop me a private message with the below details then we can look into this one further for you.
In order to pass security on the account can you please confirm your:
-Mobile Number
-Full Name and if you're the account holder
-Full Address
-Last 2 digits of sort code and last 2 digits of account number
-Date of birth

I look forwards to hearing from you further.