Missing NI contributions

My NI records show that there is a gap for 2017-2018 but the website won't tell me what's wrong, or let me pay any missing contributions. Tried ringing but no-one ever picks up. Help!

Hi,
I would advise you to call the NI helpline on 0300 200 3500 as we will need to view your National Insurance account in order to provide help.
Thank you.

Im living in Australia and have just qualified for my pension. I have already contacted the overseas pension centre to confirm I can buy back sixteen years of NI contributions - the problem is I cannot get confirmation despited call the centre four weeks ago and at the moment I cannot get through die to the delays in handling incoming calls. Am I able to get clarification from HMRC on this issue - it seems the overseas centre cannot handle the volume of calls and questions and time is running out ? Any info would be really appreciated.

Hi Ruby Aus Jaggard-Hawkins,
Unfortunately HMRC can not confirm how many years or which years would benefit your state pension the most if you were to voluntary pay for them.
Only DWP can confirm this.
If you are having trouble contacting them via telephone then you could try contacting them via the online enquiry form.
Please find a link below:
International Pension Centre
Once you have confirmation from the DWP which years and how many you need to pay for then you must fill in a CF3 application form to apply to pay for the tax years.
Please find a link below to the application form:
Apply to pay voluntary National Insurance contributions when abroad.
Apply to pay voluntary National Insurance contributions when abroad (CF83)
Thank you.