I want my money back from this *****

hello i buy a lot of stuff on the internet i have had no problems whatsoever up to now as i always make sure i get an address from whoever i am buying from .. yesterday i purchased a collection of cds from someone advertising on olx he advised me that once payment was reflecting my courier could collect so as i normally do i did an immediate transfer. he contact me told me the money was in his account and that my courier could collect yesterday. When courier arrived he wouldnt let the goods go saying his bank had told him not to let them go until 48 hours had passed, i didnt agree and told him i wanted my money back. I am now told on your 08600 number that because i did an immediate payment i wont get my money back - why? Because if i had waited 24 hours he would still have had the money in his acccount so what is the difference?? I work for myself supporting my 84 years old father on what i buy and sell on the internet this is a lot of money for me to just write off i have reported this guy to oxl security but he is still advertising please help i want my money back