Weaker than the home of the spider

I looked into your proofs and they are indeed confusing. I can honestly tell you that I want to believe in you but I am confused and do not know what to do. You speak of making istikhara, so I did that and it was confusing. You speak of visions, and I saw one that was positive and another that was not. I did not leave any door without knocking on it, so that there would be no argument against me. And I asked the people of knowledge, and they told me that this man is an impostor, but I did not care about what they said, yet I do not want to go against them and regret it. My master, you say that you can make miracles appear, such as reviving the dead, etc. And because this matter, and I mean by that your call, concerns the unseen, if you show me a miracle that proves your call then I swear by Allah that I will be a soldier of yours who wishes for martyrdom for your sake and for the sake of the religion and the creed. Otherwise, your call is weaker than the home of the spider.

We do not abrogate a verse or cause it to be forgotten except that We bring forth [one] better than it or similar to it

What is the meaning of these verses:
{We do not abrogate a verse or cause it to be forgotten except that We bring forth [one] better than it or similar to it. Do you not know that Allah is over all things competent?} [Surat Al-Baqarah 2:106]. And He The Exalted said: {And when We substitute a verse in place of a verse – and Allah is most knowing of what He sends down – they say, “You, [O Muhammad], are but an inventor [of lies].” But most of them do not know} [Quran Surat Al-Nahl 16:101]