Your ex cannot simply dictate when he sees the child and inform the child and not you.
Please ignore the "custody" comments
There has been no concept of "Custody" full or otherwise since 1989.
Indeed even the term "residence" is now a thing of the past
As Parents you are expected to agree a pattern of visits that reflect the needs of the child - and take account of distance and work demands.
If you cannot agree using Family Mediation then you can apply to the court for a Child Arrangement Order and the court will decide the matter if need be.
If the child is away for ten days then it is not unreasonable for there to be a phone call in that time - and he cannot simply tell the child when he will see him again.
If the cost of travel is a problem then he can of course offer to pay your petrol/fares!
There will be no statements requires until the final hearing - and yes when the time comes you can ask for confirmation that the child lives with you.
Please ask if you need further details