sometimes when we send coins to a customer he / she receives it fast but sometimes it takes days together to receive the coins
This can happen if either user (sender or receiver) does not have an internet connection or is on a cellular network that blocks the port used by the Android application. Both users must be connected to the Goldcoin network for the transaction to work quickly.
As long as BOTH users are connected to at least one peer, the transaction will arrive within seconds to a couple of minutes.
second can you explain what is the /satoshi:/0.7.5/protocol 60020 in the network monitor tab of the android app
This is the current Goldcoin Windows client.