You can submit an application by completing the IDR Stage 1 application form which can be requested from MyCSP. You should include all relevant information and say how you would like your dispute to be resolved.
When you have completed the form you should send it to the following address along with all supporting documentation:
MyCSP
PO BOX 2017
Liverpool
L69 2BU
Please note: an IDR Stage 1 appeal should be raised within three years of when the issue(s) occurred, or within three years of you being aware of it. The timescale may be extended in exceptional circumstances.