If you try to send a text message to a phone number that has blocked you, the message will not be delivered. The tricky part is that it is not always clear whether you have been blocked or if there is another issue, such as with the recipient's network or phone. When you try to send a text message to a blocked number, the message can only be delivered without a block in place. So, you can send a text message to a blocked number, but it will only be delivered if the block is lifted.