National Insurance refund for expats

I gather from various tax advice websites that as a UK citizen who has been working abroad for the last 7 years, I am eligible to claim a refund on national insurance contributions that have been automatically deducted (through PAYE) on income I have received in the UK during the period I have been living and working abroad. I have written to HMRC and supplied the appropriate information, but have been informed that the regulations surrounding NIC refunds for expats are currently being reviewed so they are unable to review my claim yet. This has been the response for over a year now. Whilst I totally understand that any change in regs might affect any UK income going forward, I am confused as to why the review would prevent HMRC refunding my past national insurance payments. Are HMRC seriously suggesting that the change in rules would be applied retrospectively?

Hi Boatdrinks,
Unfortunately we are unable to answer specific queries via this Forum.
We can confirm that the policy regarding all NIC payments made after leaving employment is under review and has been for quite some time now due to the complexities involved in the various types of payments.
We are sorry that this is taking so long to resolve.
If the NICs are continuing to be deducted by your employer and there is no UK Liability for NICs, you may be due a refund of those NICs.
I presume you have been liaising with our International Caseworker Teams about this and the NICs being deducted do fall into the category of deferred payments after leaving?
I am unable to provide a timescale for when this issue may be resolved or how any change in Policy may be implemented.  
Thank you.