It was a replace by fee and he has done it with the first transaction which was to the address A in my example. But since the other transaction which gone from address A and the input of A which is the output of first transaction was changed hence the tx that was to you was dropped.
I don't think it was. It looks like a fairly standard double spend.
The sender had 0.10494256 BTC in one output on address 1CKnhZmHzj45xdvvsAf3DbLWfYSX53NVMs.
He made an initial transaction to OP with TXID 2f362caac5d3fa3a1cc586f5bdbb36bcfe6446cfc112eb1cb097d9669688204a, which spent that output with a fee of 1 sat/vbyte.
He then made a second transaction with TXID 31c444900939113ad1c57277fc2904b20f77e57f76f95eee45ec119e72a6342c, which spen the same output to a different address (presumably his own) with a fee of 20.2 sats/vbyte.