At 09 . April I went to Ban Laem border station no far from Chantaburi. The thai side are there a visa agency, offered me a cambodian visa and entry and depart stamps, for 1.900 THB  They told me, I can not turn back from cambodia on my own, within one day, because, I need to spend one night in Cambodia. I went to the Cambodia border police. They said me the same. After I give up, paid the 1.900 to the agency. I have got back the passport within 20 minutes. The cambodian visa, and stamps was arranged  in order. 

I think so this was a scam, and Cambodia never imlplemented a rule, to stay one night in the country obligatory.

Are here anybody same experince, or bigger knowledge?

they are correct as it is the rule that you should stay overnight, usually you can pay them couple of hundred baht to waive the rule

I went out at Poipet once without knowing they wont let me back in. Took a taxi down to Ban Laem and was back in Thailand within 3 hours. All done on my own, no agents, and no one asking for extra money. Stamped out of Cambodia, into Thailand 15 min later. Only weird thing was being forced to go 20metres over to the Thai side to get my arrival card as some ppl at a table before departure had lots of them but wouldnt let me have one (only for their own customers or something, they said).    Almost 2 yrs ago

There is an official Cambodian immigration rule that you must stay overnight when entering by land (except when you have a multiple entry Cambodian business visa). You may need to pay a small bribe (typically 200 baht) to have the rule waived.

 

The correct price for a Cambodian visa on arrival is US$30. Thus, if willing to walk a couple of hundred meters, the in/out should cost no more than US$30 + 200 baht. I actually have never paid the 200 baht, but it requires a little subterfuge to avoid it.

5 hours ago, bogozy said:

The thai side are there a visa agency, offered me a cambodian visa and entry and depart stamps, for 1.900 THB

The cost of the Cambodian VOA is under 1000 Baht if you pay in dollars.  The other stamps are all free.

 

5 hours ago, bogozy said:

They told me, I can not turn back from cambodia on my own, within one day, because, I need to spend one night in Cambodia.

True, but for 200 to 300 baht they will waive that rule.

 

4 hours ago, Essecola said:

Only weird thing was being forced to go 20metres over to the Thai side to get my arrival card as some ppl at a table before departure had lots of them but wouldnt let me have one (only for their own customers or something, they said).    Almost 2 yrs ago

They try to sell them 100-baht, last time I was there in 2017.  One had to go window-to-window at Thai immi until someone gives you one (they are clearly in on the scam).

Grateful thanks for all replies  :)