Alright everyone pls don't wonder why it took me long to reply because I was busy with some important stuff off forum and I locked it so I could reply when convenient for me.
As for the answers.....
For the first paragraph where the issue starts, payment B disappeared for 2 reasons based on the story which are you spent the coins on a fee rate below purge fee becomes of this miners dropped it and it didn't reflect in your balance because when you came to recheck as a "Nigerian "

Naija network do their own so your wallet couldn't sync...
Both of them were still pending in paragraph 3 because currently they were in low priority on the mempool because of congestion. They landed in the same block because they were placed at same depth.

Some of you were close but didn't hit the nail on the head in some parts.
George Edward Sticky Bomb Barikui1 Felicity_Tide Hatchy Merit.s DubemIfedigbo001 Zaguru12.
Replies were very few as expected.... Anyways discussions can come in concerning this topic.