I contacted Stormfiber again and this was their reply:-
"With reference to your email, this is to inform you that if you are using VOIP/SIP services, it is considered as grey traffic and comes under PTA strong monitoring. In the recent past, PTA has setup Web Monitoring System (WMS) to curtail grey traffic. Strict actions have been taken at their end to control the concealed transmission of VOIP/VC/VPN.
StormFiber offers consumer internet services and does not provide any support or services related to VOIP/VC/VPN as it comes under enterprise solutions. Also as explained above that PTA monitors and blocks the source IP that is carrying such traffic and requires whitelisted IP with licensing documents. We don’t have any IP whitelisting mechanism being consumer service provider in nature."
Is there any way to contact PTA and get this issue fixed?