everytime when i try the viabtc accelerator it says "this transaction doesn't exit" ! any ideas why this is happening ?
Probably because of the low fee?
They reject transactions without the minimum fee.
Accelerating a bitcoin TX with a credit card payment is the epitome of stupidity.
You can also include paying a larger fee for an acceleration service than a bit higher tx which would have confirmed in less than an 3 blocks to that.
Accelerations services make sense only when you're not the (cheap) bastard that sent the money, you're the receiver.
This is what we should do - pay more fees when we really wanted the money as soon as possible. This happened to me a year ago when I withdraw .6 bitcoin to use for a very important matter and I never realized that in electrum, the fee setup was too small - so I ended up waiting for it for more than 2 weeks more or less.