go to your shop page then copy paste this code into your browser url bar. then enter your pin and click update, it will remove all items from your shop and put them into your inventory.
javascript:var forms=document.getElementsByTagName('form');var myform;for(var i=0;i<forms.length;i++){if(forms[i].getAttribute('action')=='process_market.phtml'){myform=forms[i];break}}if(!myform){alert('form not found!')}else{var sels=myform.getElementsByTagName('select');for(var i=0;i<sels.length;i++){sels[i][sels[i].options.length-1].selected=true}}
if you are using firefox pres go to your shop, press shift+f4, then remove the "javascript:" part from the start of the code i gave you, paste it into the scratchpad (that opened on shift+f4) and soon after pasting hit ctrl+r to run the code (make sure to have your focus inside the scratchpad)