Also i haven't got a phone call, maybe they do not know my number?

Thanks to everyone helping, atm im kinda worried as i do not want my parents to see this and aslo im penniless, This is the first letter i have received by the company, on the letter they say the company is a debt collection agency., they have been instructed by their client to collect the above oustanding balance on their behalf. You should read both sides of this notice very carefully and follow the instructions and reply IMMEDIATELY, if i have any queries or any of the information supplied is incorrect please contact them on the number supplied. If you FAIL to reply to this notice by the date specified, the action detailed below maybe taken. Then it goes on to say i must contact them asap as failure to do so will result in further action, the above balance includes an administration fee og £202.02 which has been added to the costs incurred by 02 in referring the debt for collection activity, in accordance with their terms and conditions. Im not sure how to go about sorting this out, this is my debt but the last i knew it was totaling near £700 not £1500

The amount is for over £1500 and is due to a mobile phone contract, i do not have to money to sort this issue out and i do not know what to do, can i get any help? The agency is Wescot