An-Naḥl: 86
"And when those who associated partners see their 'partners'..."
If they mean by "partners" their deities, then the meaning of {our partners} is: the deities whom we used to call "partners."
If they mean the devils, it is because they were their partners in disbelief and their companions in error.
{We used to call upon} means: we used to worship.
If you ask: Why did they say, {You are indeed liars}, when they were worshipping them in reality?
I say: Because they [the deities] were not pleased with their worship, it is as if their worship was not worship at all. The evidence for this is the saying of the angels: {They used to worship the jinn} (Saba': 41), meaning: the jinn were the ones pleased with their worship, not us; therefore, they were the ones worshipped, not us.
Alternatively, they called them liars in their naming of them as "partners" and "deities," to declare Allah exalted above having a partner.
If "partners" refers to the devils, it is possible that they were "liars" in their statement {You are indeed liars}, just as the devil says: "I disbelieve in your associating me with Allah before."
{And they offered}—meaning those who did wrong. Offering submission is surrendering to the command of Allah and His judgment after their refusal and arrogance in the worldly life.
{And lost from them}—meaning, became void for them—{what they used to invent} regarding the claim that Allah has partners, and that these partners would help them or intercede for them, at the moment they [the partners] lied to them and disassociated themselves from them.
An-Naḥl: 88
{Those who disbelieved and averted [others] from the way of Allah - We will increase them in punishment over [their] punishment for what they were corrupting.}