Not sure if scammer but very suspicious. (Cammighty)

I've never bought RSGP before and I decided to try Cammighty, we agreed that I would pay £100 for 400M in increments of £50 for 180M and then the next £50 for the rest but after I paid the first £50 on the 30th (after over 12 hours of waiting) he got back to me and insisted that his 'brother' (Who he just now mentions) would not trade me the agreed 180M for the £50 I paid until I paid another £50 then he would trade me the full 400M. This happend around 2am on the 31st This is NOT what we agreed on. (Trying to get the most out of me before he runs off with the cash?)

I found this suspicious and tried to argue against it as he agreed on two increments of £50 he insisted against our prior agreement but claimed he would have refunded my £50 instead of paying the 180M for it. (Seems retarded and stupid to me) He said I would not receive anything unless I pay the full £100 upfront but either way I went ahead and agreed to pay another £50 if he pays me the full 400M within 2 hours of receiving the money, we agreed to this and I sent the second £50 which was picked up at 9:30AM GMT. YESTERDAY. (31st)

It is now 8:30AM GMT (1st) (23 hours later breaking the 2 hour agreement) at this point he has the full £100 and I've yet to receive a single GP OR MESSAGE OR PM although he WAS online here earlier for a few minutes and I sent multiple PMs. He's not been on MSN (Busy status for over 24 hours, went 'offline' around 9am his time, Bulgaria) since I went to bed after sending the money yesterday early morning. Meanwhile I'm sat here with nothing. Am I just being paranoid or has he scammed me?

Username: Cammighty.

Vouches: Has quite a few. http://sythe.org/showthread.php?t=1361213 < Here
I have spoken with Kevin001 whom has vouched for him twice and is a respectable member of this forum and he has had two smooth trades with him for higher amounts (Seems strange he would scam me for £100 if he has scammed me at all?)

EDIT: I have proof of my payment and his pickup but would rather not post unless necessary. The £100 was sent in two increments of £50 via Western Union.

TL;DR He keeps changing the agreements after I send money not accepting increments and taking long breaks of not talking between me sending money (many many hours hasn't contacted me in over 24 hours after last payment) all of a sudden he has a brother who owns all the money and has access to the accounts with money even though Cammighty showed me the money himself on an account which he later claimed was actually his brother.

 

No proof of anything presented