You can terminate your o2 contract with o2 (= Telefonica ) by giving at least 3 months notice to the end of the contract term. If you wish to keep your exisiting number you need to ask your new provider to request that your number be transferred to them (called Rufnummerportierung). If the number should be transferred after the o2 contract has ended then there is nothing else you need to do. If you wish to transfer the number whilst your o2 contract is still running, you will need to contact customer services first and request a so-called "Opt-In" to have the number released early. You would then automatically be given a new number to use with o2 until your o2 contract ends.

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Thankyou very much for the quick response 



so technically my contract ends on 02.11.2017 and by giving notice can i end the contract in 3 months that is by 02.02.2017 ? 



if yes then i would like to immediately begin the process. 



and also when i joined the o2 as post paid customer it was said to me that i can terminate the contract anytime by paying 30 euros and also at the beginning of my contract period i was charged with 30 Euros which included my first month usage charges i think. 



I would be glad to get to get your help

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If your contract term ends on 02.11.2017 then you have to pay until that date. Your termination notice must reach o2 by 02.08.2017 - i.e. 3 months before - at the latest, otherwise the contract will be automatically extended by 12 months. The 30 Euros is the cost for transfering your number to another provider and has nothing to do with when you can terminate the contract.

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The 30 Euros you paid initially was probably the activation fee.

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