Absolutely.
It's a delaying tactic - getting you to wait ... and wait ... and wait for your product to turn up.
Once you leave the matter too long, the window to file a claim against the seller closes - and they will abandon you completely. If you leave it way too long, your ability to leave feedback can also disappear.
Your money is gone and your ability to warn is gone. Just be aware.
I have a standard action plan for anything that is getting on the nose....
- A week before the window closes, I will contact the seller, tell them I haven't received the item and advise them that if it doesn't turn up in the next few days, I will be raising an "Item Not Received" case. I also inform them that this is only to protect my position.
- A day or two before the window closes I will raise that case. (I always leave this gap to make sure I don't get caught by timezone differences.) In that case, I advise that I will not raise it to a claim until the end of the claim period, to allow for an item that has been genuinely delayed.
- If no item is received as this period draws to a close, I will raise the case to a claim - and I will inform the seller that if the item arrives after wards, I will advise them and we can work out how I can repay for the item.
In most cases, once the case has been opened, the seller simply refunds on the spot - and, strangely enough - the item never turns up.
There was one case, however, where I bought two monitor power supplies from a business in the USA and I received a box with only one in it. I contacted the seller and they informed me that they had sent two separate boxes. After some weeks, the second had not appeared, so I contacted them and after some back-and-forth, they sent me a replacement. (I believe their reluctance was because they felt I was trying to rip them off.) The replacement unit arrived at around the expected timeframe and I had forgotten about the missing one. That was until it turned up about a month after that. The thing had taken more than 3 months to get to me - where the other two had taken less than 2 weeks. I contacted the seller and payment was arranged and made, since the cost of sending it back made it more valuable as a spare.
Yes, sometimes, there is a genuine issue with the post - but taking a reasonable stand can protect yourself while giving the seller every chance.