Delivery time is much depends on our original / contract and payment,

Again that is also much depends on time of contract execution. If the buyer does all what he has committed, delivery would take place as it mentioned on the contract.
Any delay on that would cause the delay.

Yes off course first of all you will get the invoice from us. Then you will sign it and return the signed invoice to us, afterwards we will send you our signed contract for your signature.
2nd steps we prepare our cargo and at the same time will give you our shipping documents. There you will get our official invoice.