如果通過微信購物完成匯款後被對方拉黑，可以按照以下步驟取回款項：

首先，在微信聊天室內點擊對方的頭像，查看對方的個人基本資料。然後，選擇右上方的三個點，進入資料設置。在資料設置頁面，點擊最下方的“投訴”選項。在投訴頁面，選擇第二個選項“存在欺詐騙錢行為”，然後選擇“收款不發貨”。接著，在詐騙資金的支付方式中選擇“微信支付”。此時，需要把相關的聊天紀錄提供給微信團隊進行審查。

接下來，進入微信錢包，點擊右上方的“帳單”選項，然後找到被詐騙的帳單，點擊進入後選擇“對訂單有疑惑”。選擇“交易被騙”，再點擊“投訴收款方”。在投訴過程中，簡單描述事情的經過，並提供相關的照片和證據。審查完畢後，如果投訴成立，對方的帳號將會被封鎖，並且將拿回被騙的款項。

If you have been blocked by the seller after completing a payment through WeChat shopping, you can follow these steps to retrieve your funds:

First, click on the other party's profile picture in the WeChat chat room to view their basic personal information. Then, select the three dots in the upper right corner to enter the data settings. In the data settings page, click on the "Complaint" option at the bottom.

In the complaint page, choose the second option "Fraud/Scam" and then select "Payment received but no goods delivered". Next, in the fraudulent funds payment method, select "WeChat Pay". At this point, you need to provide the relevant chat records to the WeChat team for review.

Then, go to WeChat Wallet, click on the "Bill" option in the upper right corner, find the bill related to the scam, click to enter and select "Question about this transaction". Choose "Transaction was fraudulent" and then click "Complain about the payee".

During the complaint process, briefly describe the situation and provide related photos and evidence. Once the review is completed and if the complaint is upheld, the other party's account will be blocked, and the scammed funds will be returned to you.