The Pakistan Telecommunication Authority (PTA) said the ban was enforced last month due to protests from parents and lawmakers, but critics warn it is the latest attempt at creeping censorship.
The PTA first pulled the plug on dirt-cheap chat rates and late-night discounts in November, but operators simply started offering the services under different names.
So the regulator tightened the ban late last month, ordering telecommunication companies to scrap immediately "all kinds of chat services, irrespective of the time of day".
In Pakistan girls can be beaten or even killed by male relatives if there is any hint they are having a relationship and parents like to strictly control the marriages of their offspring.
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A 20-year-old university student who did not want to give his name told AFP that the ban had hit him hard as he is now unable to chat with random girls and find new dates.
"It was so inexpensive and an easy way to find a date," he added.
The 25-year-old manager of a boutique in Islamabad told AFP that he had found the "love of his life" through the service.
"I am going to marry her," he said.
"We chatted, we exchanged numbers, we started talking and I was surprised to find out that she lived nearby," he said.
There is no public data about how many people used the romantic chat, but of the 68.6 per cent of the population with access to a mobile phone, it is likely to have been a small number.
A customer would dial a particular number after which a computer generated voice or text message guided subscribers through various options.
For example, if you want to chat to a girl press 1, a boy press 2, then you select your preferred age group before being connected to another caller by SMS conforming to your criteria.