Data sim not activitated

Very very disappointed with the service of one2one .on the 3Aug 2017.I have app**** for a data sim card and it was delivered in three days time, however the simcard as per the letter that came with the package its says it will be activated with in 72hours time. But to my shock and surprise till to date the sim card Its not active... When I phone to inquire about it they say they had technical problems or what ever. They say the sim card was active on the 24th Aug..you can just ask yourself 72hours and 21days...but I don't care anymore I just what to cancell this contract and please credit me on my account since I have been already billed for something that's not working ....just cancelled it...I have nevar used it .