Praise be to Allah.
The ability to do Hajj is one of the conditions of it being obligatory. If you are able to afford it and to pay the installment that is due at the time of Hajj, then you have to go for Hajj. If you cannot to pay the installment and go for Hajj at the same time,then you must give precedence to paying off the installment that is due, and delay Hajj until you can afford it, because Allah says (interpretation of the meaning):
“And Hajj (pilgrimage to Makkah) to the House (Ka‘bah) is a duty that mankind owes to Allah, those who can afford the expenses (for one’s conveyance, provision and residence)” [Aal ‘Imran 3:97]
And Allah is the Source of strength.