The mother is using visitation as a power weapon and causing untold distress. The child is now 21 months old.
You have no rights to parenting time because you have no parenting plan. If you want parenting time (visitation), you will have to petition the court for a parenting plan. Paying child support is not related to the parenting plan, in that, paying child support does not give you rights to visitation. You need a court order. She is able to dictate when you see the child because you have not pursued your legal rights. You need to do so ASAP!