How to cancel O2 contract, if no router and internet installation done yet.

Hello O2,

I have requested for a new internet connection last month Decemeber. I have no internet conenction yet. However I do not wish to proceed further with O2 as communication with customer care concerning problems which I have is impossible as no one speaks english.

No router was provided to me yet and no installation done. I have no email with me other than a single booking reference Id : 49934441.

Please let me know how to cancel and I shall do the same.