I am sorry to hear about your situation.
This reminds me of my situation some years back. I will share my story with you before giving any advice.
I also said NO to my cousin (he was both maternal and paternal cousin!) and it wasnt welcomed very well. In our family, everyone gets married with their cousins or distant cousins and here I was saying NO to this cousin. I had a long list of reasons why I didnt want to marry him but still my parents didnt listen to me. After many discussion I was promised OUTSIDE MASJID AL HARAM in Mecca that I will not get married to this cousin!!! This was during my umrah trip with my parents andmy uncle who lived in Jeddah told them to take me to Pakistan from there cuz otherwise I would never travel to Pakistan with them. So they tried so much to find tickets for Pakistan and perhaps one of my million duas came true and they didnt manage to get airline tickets from Saudi to Pakistan. Then I was promised not very far from the holiest place for Muslim - the Kaaba - that they will not marry me to this guy if I went to Pakistan with them after 6 months when my other cousin was getting married.
So I believed in them. I thougt that they promised me this at such a sacred place and went along for the family wedding in Pakistan. Once that wedding was over, everyone started to prepare for MY wedding!!!I made a huge deal about it, said NO, explained to them why I didnt want to marry the guy and it was OBVIOUS why me and him didnt make a good match!!! My khala even bought loads of mithai and was preparing for the nikkah and was furious that all the mithai got wasted due to me being so stubborn! the worst part was that we lived in the same house as he is my dad’s brothers son as well. so I woke up for hell everyday for God knows many days. They cancelled my return, were hiding my passport and wouldnt allow me to answer any phone call either. I felt like a hostage!!!
I was threatened that if I ddint marry him they would kill me and cut my body into pieces and throw in the river in the area…it was all a big chock for me!!!
At the end they got me. I was forced into nikkah with that cousin. I didnt speak to anyone after that day eventhough we were living in the same house. Then they demanded that I give them a guarantee that I will appy for his visa. I told them that this can only be done once I am back home so they arranged for my return ticket.
Once I got back home, I sent an email to the embassy of my country in Pakistan and informed them that I have been forced married to this person and will never accept him to get a visa on my name. I did that in case I would get forced to apply for his visa.
I decided that I would apply for divorce but it wasnt an easy process as my sister got married to his brother on the same day.So I waited till her husband got visa and they had been together for some time.
It was a living torture of 4 years and everyday was like hell. I used to cry so much and only thing that helped me through this was my strong faith in Allah - that He will help me.
I got divorced 4 years after that nikkah in Pakistan. and a year later I got married to the loveliest person on earth:) I moved to another country when I got married and once I got the mental peace to relax I collapsed both physically and mentally. It took me many years to re-built myself and become stronger.
I still have traumatic memories and have a huge trust issue towards people due to what I have experienced.
My advice to you is that dont go to Pakistan. you will be much more vulnerable there than where you are now!!!It is your parents responsibility to say no and it can be done on phone as well. they dont need to go to Pakistan for that. thats just an excuse to take you there and perhaps force you to get married there!!!
Being 28 doesnt mean that one should hasten into a marriage with a cousin one doesnt like. Try to find other options around you. your parents might not be willing to do that but its your life and you deserve to be happy. Look around and see if there is anyone that might be suitable for you.
Keep praying to Allah that He guides you all and finds you the best option. Pray 2 rakah hajat everyday and make dua that Allah eases your situation.
The thing wit emotional blackmailing is that one just needs to stay firm and defeat the other party by being firm!!! wish you all the best and pray that Allah eases your situation.