Never had a problem - if parcels aren't arriving it's probably a problem local to you.
However, if they don't arrive you don't pay
My
last order at AliExpress was a nightmare. I wanted to explore using Modbus, so I ordered many different pieces from different vendors. The problems started when my shipping was "upgraded" and separate items were consolidated into larger shipments. Somehow in that process, my address was screwed up. The street name became the city. The state name became the street. All sorts of variations. I notified some of the sellers of the issue and the replies were "We shipped to the right address. Just wait a little longer."
I watched as my packages were sent to non-existent addresses across the country. I received about about 3 items out of 20 valued at around $25 out of a $200 order.
I filed disputes on items as messages "no such address, returned to sender" started coming in. I got helpful responses that included "check with your neighbors. Maybe they have your package." Sure, the mangled address was 2000 miles across the country, and I should check with my neighbors.
I received some refunds, some of which were for only a fraction of the price paid. Even after it was confirmed that the packages went to a non-existent address and were return.
My account at Ali was blocked for "abusing the dispute process." Keep in mind, they had my correct address, because I received several items which were delivered to the proper address. Their shipping partners changed the addresses and screwed things up.
All told, I gave up in frustration still owed about $30 on the $200 order. And of the 3 items delivered, one was the wrong thing.
I don't think my experience was typical, but it shows what can go wrong. AliExpress is a large number of vendors operating as one company. There's no easily reachable point of contact that will resolve problems.
My advice: Order one or just a couple things at a time from AliExpress, and don't order more until those items are delivered. Trying to keep track of 15 or more separate orders at the same time was an exercise in frustration, with many hours lost trying to get things sorted out.