Cannot limit account usage

[bookandhost]

I need guidence to limit the account usage like if i have alloted 25MB space it should work only till 25MB space but infact its even taking 40MB and more and we are unable to trace things, or if we even trace client refuses to pay saying its faulty system you are not able to stop usage beyond the limit. I m using Smartermail even that space sometimes doesnt get calculated in total usage, i need total usage space to be calculated inclusive of mails, database, ftp, logs, can someone guide me on this process which would be helpful for me to maintain the process.

[RFH Reseller: HostCan]

you will create a reminding email under helm. When somebody goes over his limit you will recieve email and you will disable it manually. Im doing this way.