No assistance from Momentum

Momentum administers my staff pension fund.There is absolutely no service to clients as all attempts to contact them have failed. In addition to not receiving a response to my mails, I keep getting cut off at their call centre. I have some options available to me as I have now resigned from the fund however I cannot access these options due to these barriers I face. Should I not be able to access these options or should I need to claim on the risk benefits please note I will hold Momentum responsible. So please treat this post as my formal complaint that in failing to rectify this, I will refer the matter to the pension fund adjudicator and to the Long term insurance ombudsman accordingly.