There seems to be a lot of confusion here...
You sent 0.00654146 BTC (~US$26) to 3E2M262zMphpi6mCd6NvZfA113QcbTxWKr around the 15th March, in this transaction:
https://www.blockchain.com/btc/tx/8e2ba5985a025caa11cc109b57160aeb3ae542cc4d86fe6450eb2034cf6226ccWhat exactly are they claiming? That you didn't send it? That they didn't receive it? or that you didn't send enough?
İs that possible to any double spend error on site ? Because it seems 46 euros order total but ı've ordered 23 euro
Were you supposed to send €46 but you only sent €23? or were you trying to send €23 and they say they got €46?
Note that "Double Spend" is not sending money twice... it doesn't mean you've accidentally sent them 2 transactions or paid the vendor twice etc... it is a (somewhat confusing) term used to describe a situation where you can create and broadcast two different transactions using the same coins.
Generally, this is done to try and trick or scam a receiver of the first transaction that they have been "paid"... but it is the 2nd transaction that gets confirmed, which sends the coins back to the an address owned by the scammer. It is actually quite difficult to pull this off in practice... as most nodes will identify a "double spend transaction" for what it is and refuse it as being "invalid".