Well, the PCI standard is not well-known for being at the forefront of security.
But they are indeed mandating that old TLS versions be disabled, not just new ones enabled: (emphasis mine)
All entities must cutover to use only a secure version of TLS (as defined by NIST) effective 30 June 2018
The deadline for supporting newer TLS versions was actually in 2016.
I don’t blame you for being confused. Everyone is confused. I am also confused as to whether they find TLS 1.1 to be acceptable. This seems to say it is, but my PCI automated scanning vendor (and the OPs payment gateway) seems to think it is not. Maybe the NIST recommendation changed in the interim? (I’m going to disable it anyway. )