Phone doesn't actually ring - inbound number sends a text message to say you have missed a call, but caller didn't leave a message.

I have had several like this in the past before. Scammers are testing mobile number sequences to see if anyone calls back. If not sure, test the number from a landline. If you call back from your mobile number, the scammers will obtain your correct number and use if for their own personal gain. Ignore the numbers and just Block, Block, Block.