Как нибудь так попробуйте
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<title>Untitled</title>
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<div align="left">We accept payment in the form of <strong>PayPal</strong> (preferred method). Payment must be made via eBay. Items will not ship until payment is received. We are required to collect 8.875% sales tax to all orders shipped to NY state residents. This will be added to your order upon checkout. International orders can only be made via PayPal. Please contact us via Ebay for more information. <br></div>
<button id=bch>Заменить</button>
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<script>
let rex =/We\saccept\spayment\sin\sthe\sform\sof\s<strong>PayPal<\/strong>(.+)Please\scontact\sus\svia\sEbay\sfor\smore\sinformation\.\s<br>/;
let ss =`We accept payment in the form of Credit or Debit card.<br>
Items will not ship until payment is received.<br>
We are required to collect sales tax to all orders.<br>
This will be added to your order upon checkout.<br>
Please contact us for more information.`
document.getElementById('bch').onclick = () => document.body.innerHTML = document.body.innerHTML.replace(rex, ss);
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