All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Your question encompasses many different matters. We will answer them as follows:
If you are saying that your boss allows you to pray the Friday prayer but does not allow you to pray other prayers while at work, even if the timing of the prayer expires, or that you do not pray except the Friday prayer, then this is one of the grave major sins. You have, in this case, to repent to Allah and perform other prayers.
The Prayer is the backbone of the religion, and it is the one which distinguishes between Islam and Kufr (Disbelief). The Prophet said: “Between a person and disbelief and polytheism is abandoning the prayer.” [Muslim and Ahmed]
As regards pretending leaving your work in order to get the Social Welfare Allowance, which requires a person to totally stop working, then this is not permissible, as the Prophet said: “The Muslims should honor their conditions.” [Abu Daawood]
The Prophet also said: “Whoever cheats is not one of us.” [Muslim]
With regard to working secretly in this company so that they would not pay tax on you, then imposing taxes on people without right is one of the major sins, whether it is by a non-Muslim or a Muslim country. This is taking people's money without right. The Law-maker warned us against this.
Imam Ahmed reported that ‘Uqbah Ibn Aamir narrated that the Prophet said: “Whoever imposes taxes will not enter paradise.” So if this is the case, then there is no harm to help this company avoid paying taxes, or avoid paying some of them, whenever possible without causing any harm.
However, if these taxes are imposed lawfully, for example, in order to provide the necessary services like education and health and the like, and if the treasury is unable to offer such services unless it imposes taxes, then, in this case, it is not permissible for you to help this company to avoid paying taxes, even if that leads you to leave your work if you are not in a state of necessity. In fact, when a Muslim enters a country with a pact, and its laws are not contrary to the Islamic Sharee’ah, then it is incumbent upon him to obey these laws and not help people avoid respecting these laws. The pact requires this. Allah says (what means): {And fulfill [every] commitment. Indeed, the commitment is ever [that about which one will be] questioned.} [Quran 17:34]
Concerning your debts, you have to pay them to the bank –whenever it is possible for you to do so. You have to pay back the exact amount without paying the interest if it is possible and if this does not cause you any harm.
With reference to your intention to perform Hajj (pilgrimage), you have to first repay your loans, and if you have enough money remaining after that, you have to go for Hajj if you have not previously performed it.
Finally, we advise you to fear Allah, The Most High, and endeavor to obey Him. Whoever obeys Allah, Allah will make a way out to his anxiety, and solve his difficulties, and will provide him from sources he never could imagine. Allah says (what means): {And whoever fears Allah - He will make for him a way out. And will provide for him from where he does not expect. And whoever relies upon Allah - then He is sufficient for him. Indeed, Allah will accomplish His purpose. Allah has already set for everything a [decreed] extent.} [Quran 65:2-3]
Allah also says (what means): {And if only the people of the cities had believed and feared Allah, We would have opened upon them blessings from the heaven and the earth; but they denied [the messengers], so We seized them for what they were earning.} [Quran 7:96]
You have also to supplicate with the supplication of the Prophet “O, Allah, I take refuge in you from anxiety and sorrow, weakness and laziness, miserliness and cowardice, the burden of debts and from being overpowered by men.” [Ahmed with a sound chain of narrators]
Allah knows best.