Activated new phone and new texts started coming through in the notifications stack, but when I went into my actual messages - they are nowhere to be found.

My new and old phones were inactive for about 12 hours after issues with switching with the phone company. I was finally able to speak to customer service and get the new phone activated. After this, I received about 15 new texts that came through while the phones were inactive. I tapped on one to open from notification center and they did not show up. I went into messages and none of the new texts were visible. Is there a way to find them or get them back? These came through my phone number and most were not through iMessage.