Exxpozed outdoors - Exxpozed scam57

On **/**/****, I bought * items from the Exxpozed online shop that costed €***.** in total. They charged me €*,** standard shipping fee to Greece. Two days later, I received a message from them saying that one of the items (that was a pair of outdoor sandals) was sold out and asking if I wanted to buy something else from their list of products. I had to reply in * working days, otherwise, they would refund me the money of this item and ship the order. I replied asking them about another item, but I kept receiving automatic e-mails saying that they are too busy and they will answer in ** hours. I contacted them from their chat, but it was offline at the moment and I never got any reply to my questions. On */**/****, I got a "delivery status update" e-mail saying that the total cost of my order was €***.** (subtracting the item that was sold out) and a second e-mail saying that they already shipped my order (without giving any reference number to track my order). I checked my back account and the money was taken and in the meanwhile I tried to contact them through e-mails. I got nothing but automatic e-mails back. I also asked through their website to call me on my mobile phone on a specific time and they did not do that neither. I tried to call them by phone, but it was impossible to find them too. Finally, I contacted them through their online chat and they replied to me giving me the reference number of my order for the first time, after many attempts to get in touch with them. So, I decided to send them an e-mail telling them that I am very disappointed from their customer service and suggesting to either send the extra item that I wanted without shipping costs or to cancel/revoke my order completely. On **/**/****, I received a reply saying that they have already shipped my order and giving me the tracking number. No word about the option of revocation of the order (although they offer this option through their website). After that, I contacted them online to express my disappointment and they claimed that because of the way of paying (it was a debit card actually, but they said it was a credit card) it was impossible to add another item on my order. Anyway, I decided to wait for the order to arrive.
My order arrived on **/**/**** and I was disappointed again to find that one of the items (the hiking boots that I needed for the winter) was wrong, meaning that it was not matching the description on their website. Before I ordered they had made sure that it has a special feature, which it didn't have in the end. I sent an e-mail asking to return the item asap without paying the shipping costs and I demanded full refund of the price of the item. They did not reply the next day, so I contacted them through the online chat. They acknowledged their mistake and asked me to either keep the product with €** discount OR return it and be refunded for the return shipment costs and the price of the item. I agreed with the second option.
Of course, I also asked to be refunded for the first shipping costs of my order because * out of * ordered items (corresponding to the **% of the money that I was supposed to pay) were cancelled or/and wrong because of their mistakes. Plus, they have caused all this distress to me because of their bad customer service.
They replied that they will not pay for the first shipping costs and that if I do not accept their options, they will NOT pay for the return shipment, because they don't really have to do it. I see this as blackmailing and I do not accept it.
I am asking to be fully refunded for the price of the wrong item that they have sent to me, including the price of the item,the first shipping costs to me and the return shipping costs to them.